Concealment, Revelation, and the Mechanics of Desire
Evidence that sex sells can be seen in movable books and ephemera as far back as the 1500's. Venetian flap books of the sixteenth century represent one of the earliest forms of interactive erotic print, in which seemingly modest images conceal hidden scenes revealed through liftable flaps. Produced in a culture renowned for its sensuality, these works invited the viewer into an explicitly participatory experience that has been described as “quintessentially voyeuristic. The New York Public Library’s 2017 exhibition Love in Venice brought renewed attention to these rare Venetian flap books. These books often invited viewers to lift garments or curtains to reveal hidden imagery. As curator Madeleine Viljoen noted, these works “were designed with the titillation of the viewer in mind.” as well as "quintessentially voyeuristic." The exhibition included Hypnerotomachia Poliphili, one of the most iconic books produced in Venice to explore ideas of desire, and flap books revealing such things as the undergarments of Venetian prostitutes. The exhibition also featured Le vere imagini et descritioni delle piu nobilli citta del mondo (1578), published by Donato Bertelli, a bound volume composed of engraved plates depicting maps and figures from major sixteenth-century cities. Within its section on Venetian courtesans, the book incorporates minuscule liftable flaps—an early form of interactive “peek-a-boo” engineering—inviting the viewer to reveal hidden details such as undergarments or elevated chopines. Additional works in the exhibition included related flap engravings, such as a scene of a woman accompanied by a chaperone in a gondola, in which lifting the flap exposes a concealed embrace between lovers. Preserved today in the Spencer Collection at the New York Public Library, these works are considered a landmark in the early history of movable and interactive books, demonstrating how mechanical engagement was used centuries ago to heighten both curiosity and sexual titillation. For additional images and contextual information, see the New York Public Library’s exhibition materials for Love in Venice.
Suzanne Karr Schmidt’s Interactive and Sculptural Printmaking in the Renaissance (Brill, 2018) provides the most comprehensive genealogy of early interactive prints, cataloguing over 190 surviving single-sheet examples from 1466 to 1700. Schmidt notes that as many as 190,000 such prints may have circulated in Europe during the sixteenth century alone, underscoring how widespread these interactive formats once were. Particularly relevant to this chapter, is her discussion of late sixteenth-century flap engravings of women—described in Chapter 12, “Liftable Skirts and Deadly Secrets”—which document a cluster of mildly erotic prints that invited viewers to lift layered paper elements to reveal concealed imagery.
While erotic movable mechanisms were employed across a wide range of printed materials, intended for adult audiences, this category—particularly in ephemeral or risqué forms—remains comparatively underdocumented in existing scholarship. Image from this 1920's card states Pour messieurs seulement’ (‘For gentlemen only’), ‘Pour me tirer’ (‘Pull here’), and ‘Voir nue ici’ (‘See nude here’) to explicitly direct the viewer to activate the transformation.
With these movable cards and sheets, what is hidden invites discovery; what is revealed transforms the viewer into a participant. While movable books are most commonly associated with children’s literature, their use in adult-oriented material has a much longer history than is often assumed. Risqué and erotic movable works were already being produced in the early nineteenth century, demonstrating that interactive paper mechanisms were never confined exclusively to juvenile audiences. Movable mechanisms were particularly well suited to early erotic material, as they allowed imagery to remain hidden until activated by the viewer, shifting the act of transgression into one of participation.
Examples documented by Stephen J. Gertz on Booktryst (Gertz, Stephen J. “A Rare and Revealing Erotic Movable Book from 1846 (May Be NSFW).” Booktryst, August 1, 2012) include Variations de l'Amore, a rare work consisting of a suite of nine numbered, gilt-bordered watercolor plates with overlaid flaps. At first glance, the scenes appear innocuous; however, when the overlays are lifted, they reveal explicit content beneath, transforming the viewer’s experience through interaction.
Gertz further identifies other early examples, including Moeurs de Paris (ca. 1835) is a clandestinely produced French work that reflects the thriving underground market for erotic and socially transgressive print culture in early nineteenth-century Paris. Often issued with a false London imprint to evade censorship, the book is associated with artists such as Achille Deveria, whose refined yet suggestive illustrations capture the fashionable world of Parisian society while hinting at its more intimate realities. What sets certain copies apart is the inclusion of movable overlays—delicately engineered paper elements such as doors, windows, and other hinged elements tallow portions of the image to be lifted or transformed—revealing hidden scenes beneath.
In the 19th century, movable erotica functioned as a high-stakes game of hide-and-seek, where sophisticated paper engineering was used to bypass strict censorship laws. While the century is often remembered for its outward prudery, it was actually a "Golden Age" for mechanical ingenuity in adult publishing. These books and cards—produced clandestinely in cities like Paris, Vienna, and London—relied on the physical participation of the viewer to complete the "offense." By lifting a flap, pulling a tab, or holding a card to a candle, the reader transformed a static, respectable image into a transgressive act. This made the 19th-century movable book more than just a novelty; it was a tactile medium that allowed for a private, interactive experience of the forbidden, safely hidden behind the "innocent" facade of a standard book binding or a common playing card.
Books such as Les portes fermées ou Les doubles surprises (ca. 1820) ( translates to Closed Doors or Double Surprises) demonstrate how flap devices were used to create surprise including the erotic kind. The book employs literal cut and hinged “doors” and “windows” within its printed scenes, inviting the reader to open these elements and peer into private interiors. Behind these openings are more overt glimpses of intimate encounters—lovers embracing, undressing, or otherwise engaged in private acts This innovation marked a significant shift in the reading experience, requiring the reader not only to observe but to act, thereby transforming the book into an interactive object. By this point, the flap had moved well beyond its earlier scientific and anatomical uses and had become a flexible storytelling device. Instead of revealing hidden organs or technical information, it now revealed scenes, characters, and visual punchlines, showing how an older paper mechanism could be adapted to create suspense, humor, and playful revelation.
Peter Mendes’s Clandestine Erotic Fiction in English 1800–1930 (1993) demonstrates that a wide range of popular Victorian print forms—including games, novelties, and illustrated miscellanies—had clandestine erotic counterparts produced through overlapping trade networks. In some cases, these works adapted familiar mechanical formats, such as rotating dials or volvelles, substituting suggestive or explicit content for the conventional fortune-telling or instructional text.
In the nineteenth and early twentieth centuries, erotic cards were popular objects that could be easily concealed, shared, or circulated. These cards used a wide range of movable formats designed to create a reveal or simulate the progressive removal of clothing.
The Biedermeier-era (1815-1848) German Zugkarten (pull-cards) included some with hidden erotic scenes — documented by Yasmin Doosry in Käufliche Gefühle (2004) — While the exhibition and book primarily showcase "decent" middle-class sentiments, there is a sub-segment of this genre that Doosry addresses representing paper novelties sold as innocent gifts but containing movable mechanisms that revealed suggestive imagery. Many of these 19th-century pieces are often classified in bibliographies as "gallant" or "amorous" scenes. They were frequently "hidden" not just for shock value, but to navigate the strict social censorship of the Biedermeier period. She specifically highlights that because these items were "purchasable" (Käufliche), they represented a shift where even the most "private" or "naughty" feelings became standardized commodities available at stationery shops and fairs.
Lift-the-flap mechanisms were used to create a direct reveal or enable successive layers of clothing to be “removed.” Pull tabs provided rhythmic animation, allowing figures to move back and forth or up and down; this was the primary mechanic behind the “saucy” Biedermeier cards. Venetian blind mechanics allowed a single pull to transform a scene—for example, shifting from a fully dressed figure in a parlor to complete nudity in a bedroom.
Peep shows created layered, three-dimensional interiors, such as private rooms, placing the viewer in the position of a literal voyeur.
Hold-to-light formats concealed imagery even more discreetly: a hidden erotic image was printed on the reverse of a thin sheet or within a sandwiched middle layer, remaining invisible until backlit by a candle or lamp. This allowed erotic content to be embedded within otherwise ordinary-looking playing cards or postcards, with the “reveal” occurring only under specific lighting conditions. To see examples see World of Playing Cards. “Translucent Cards (France). https://www.wopc.co.uk/france/translucent/translucent-2
The early 1900s saw a massive trend in erotic movable cards and postcards. You will find fewer books from 1910–1940 and more cards. These often used a simple “flap” mechanic—for example, a postcard of a woman in a large hat where the hat brim could be lifted to reveal her face (or more).
After WWI, and especially by the 1940s and 50s, the “saucy” movable card exploded into a mass-market industry. The “Stag” era saw mechanical cards become staples of bachelor parties and joke shops. The engineering became simpler (basic pull-tabs or “shaker” cards) so they could be printed and assembled by the thousands. While 19th-century works were often genuinely erotic or romantic, 20th-century movables leaned heavily into puns and “naughty” humor. The 1950s “nudie” pull-tab cards were more about the gag than high art.
Why not more books in the late 19th and early 20th century? The legal risks for publishing erotic movable books during this period were severe, often resulting in prison time, heavy fines, and the literal destruction of a publisher’s inventory. Because these books were interactive, they were frequently viewed as more “corrupting” than text alone, making them prime targets for anti-vice crusaders. The Comstock Act criminalized the use of the U.S. Postal Service to distribute “obscene” materials, including books, pictures, or “mechanical” representations of an immoral nature. Similarly, the Obscene Publications Act empowered British authorities to search premises and seize any “obscene” materials intended for sale or distribution.
In the late twentieth century, a growing audience for adult-themed titles introduced humor, satire, and overtly suggestive content into the medium. Such works, while often humorous in tone, continue a long-standing tradition
The adult pop-up book was truly “re-invented” for the mainstream in 1983 with The Naughty Nineties: A Saucy Pop-Up Book for Adults Only by Peter Seymour, published by Price Stern Sloan for Intervisual Communications, with paper engineering by Keith Moseley and John Strejan. It was part of an Intervisual Communications system in which they designed the intricate paper engineering and artwork, manufactured the books—often in specialized printing plants in Colombia or Asia—and then licensed the finished product to a mainstream publisher such as Price Stern Sloan, who would place their imprint on the book and distribute it to the public. The book’s lightly erotic themes use movable mechanisms to animate playful and risqué scenes, such as “The Bloomers Incident.” It employed Victorian aesthetics to bypass 20th-century stigmas, framing adult pop-ups as nostalgic art.
This was followed by another title by Peter Seymour, The Roaring Twenties: A Spicy Pop-Up Book for Adults Only (1984), with paper engineering by Rodger Smith and Dick Dudley. The work was published by Price Stern Sloan Publishers, Inc., Los Angeles, in 1984, and produced in association with Intervisual Communications. Styled after the Jazz Age, the book features flapper-era imagery, playful mechanical interactions, and pull-tab-activated scenes that reflect both the visual culture and perceived social freedoms of the 1920s. As noted on the title page, “Youth was flaming, music was hot, life was high … and sex had plenty of fans!”
A reproduction of The Naughty Nineties has been referenced by David A Carter in a Facebook post dated April 18, 2024, in connection with Blossom Books. In that context, Carter indicates his involvement alongside Jim Diaz, with mention of a focus on international publishing, particularly in the Japanese market. As founders of Blossom Books and co-authors of The Elements of Pop-Up, both are widely regarded as leading figures in the field.Carter began his career as a young paste-up artist on staff at Intervisual Communications, and The Naughty Nineties was among the first books he worked on—making his connection to a potential reproduction especially notable.
The Naughty Ninetiespaved the way for modern titles such as Pop-Up Kama Sutra (A Bonanza Pop-Up Book) (1984), illustrated by Bob Robinson, which uses movable mechanisms to animate sexual positions based on the Kama Sutra, the classical Indian treatise on the art of love. This original edition was conceived and paper-engineered by Jonathan Biggs and published by companies including Aidan Ellis and Bonanza.
A later version, The Pop-Up Kama Sutra: Six Paper-Engineered Variations (2003), also credits Jonathan Biggs for the engineered variations that present the text’s “acrobatic positions” in three dimensions. Depending on the region, it was published by Harry N Abrams, Stewart Tabori and Chang, or Collins and Brown.
More recently, The Pop-up Book of Sex (2006), published by Melcher Media (It Books), features paper engineering by Kees Moerbeek and uses high-tech “jiggle” mechanics and paper springs to simulate what the book calls “getting busy.” For those interested in further study (content may be explicit), examples of the pop-ups can be viewed on the collector reference site Pop Up Feerie Livres Animes. https://www.pop-up-feerie-livresanimes.fr/the-pop-up-book-of-sex/
Today, what was once a “forbidden” mechanical secret is now a celebrated form of paper engineering, blending education, humor, and three-dimensional art.
Image from The Naughty Nineties
For more information on the history of erotic Mechanical Paper :
Bert Sliggers, a Dutch curator and historian specializing in the history of erotica and collecting practices, has produced one of the most significant modern studies of interactive erotic print material in his 2023 Dutch language publication Vouwen, klappen, trekken, draaien. Pornografisch drukwerk voor de ongeletterde (Walburg Pers) - Translation "Folding, Flapping, Pulling, Turning: Pornographic Printed Matter for the Illiterate" . A former curator at Teylers Museum in Haarlem and a long-time collector of rare printed ephemera, Sliggers draws extensively on his own collection to document what he describes as a largely hidden corpus of European erotic material produced between approximately 1850 and 1950.
At the heart of Sliggers’ research is the idea that these works function as what he calls “ingenious systems.” You don’t just look at them—you interact with them. Lift a flap, pull a tab, flip a panel, turn a wheel, unfold a strip—and suddenly the image changes. A proper Victorian figure becomes something far less proper. A quiet scene turns into a joke—or something more explicit. The mechanics aren’t decorative—they are the experience.
And there’s more variety here than most people realize. Some rely on simple lift-the-flap “reveal” tricks. Others use pull-tabs to animate limbs or shift entire scenes. There are rotating discs (volvelles) that align images in suggestive ways, and accordion-fold (leporello) sequences that play out like a visual strip when extended. Sliggers even documents more complex constructions—slatted transformations and layered paper systems that only work if everything moves in perfect alignment. These weren’t crude novelties—they were carefully engineered.
The engineering itself is part of the appeal. Tiny metal fasteners—split pins—act as hinges, allowing parts to pivot, swing, or snap into place. In some examples, the mechanism is so well executed that the transformation feels almost instantaneous. And in many cases, there’s no publisher’s name at all. That’s not an accident. As Sliggers points out, this was a kind of “secret art.” The identity wasn’t printed—the trick was the signature. Collectors recognize the construction, the movement, the ingenuity.
Sliggers places most of this material in what he calls “low-culture” erotica—made for a broad audience, often non-literate, where everything is communicated visually. These were affordable, widely circulated novelty objects. But he also identifies a much more refined tier—“cabinet pieces.” These were built to last: heavier cardstock, metal pivots, sometimes multiple layers of translucent material. Instead of a quick reveal, they offered something closer to a performance—objects meant to be shown, handled, and admired in private settings, where the sophistication of the mechanism itself signaled taste, access, and even status.
What really makes these objects fascinating is how clearly they were designed with risk in mind. They’re small. They close instantly. And on the outside, they often look completely harmless—a dressed figure, a landscape, something ordinary. Then one quick motion—a pull, a flip, a turn—and the hidden image appears. Just as quickly, it disappears again. In a period when erotic material could be confiscated or prosecuted, that ability to control the reveal wasn’t just clever—it was practical.
Sliggers connects this directly to the legal climate of the time. Laws like the Comstock Act of 1873 in the United States—and similar pressures in Britain—meant that distributing explicit material carried real consequences. That helps explain why so many of these objects feel designed to be handled discreetly, almost defensively: shown briefly, closed instantly, and slipped away if necessary. In Victorian London, that world had an address. Holywell Street—later demolished in 1901—was known as the ‘meridian of London’s booming pornography trade,’ packed with shops selling erotic books and prints, even as authorities tried to shut them down. It was notorious, heavily policed—and thriving anyway (By the early twentieth century, this trade had become more organized in the United States. As documented in Bookleggers and Smuthounds, dealers sold erotic material through coded language, mail-order schemes, and disguised publications—often presenting explicit content as ‘educational’ or ‘scientific’ to avoid prosecution.)
There’s also another not so surprisingl international story behind them. Many were marketed as “French”—a label that carried a certain promise of sophistication and sensuality—but the mechanical precision of the designs often points toward German engineering traditions, especially in places like Nuremberg. In other words, what looked French on the surface may have been engineered somewhere else entirely. Branding and manufacture didn’t always match—and that disconnect was part of how the system worked.
The book also includes a substantial section on ‘home industry’—erotica made by hand by amateurs—as well as a discussion of early 20th-century visual technologies, showing how these paper mechanisms existed alongside, and were eventually overshadowed by, emerging media such as early cinema and 3D stereoscopy.
Sliggers also makes it clear that these objects were not limited to single cards. In a number of cases, they take on more extended, book-like forms—small-format printed pieces that unfold, sequence, or transform across multiple panels. Leporello (accordion-fold) structures, for example, allow a narrative to develop visually as the object is extended, sometimes revealing a larger or more complex scene when fully opened. Other examples incorporate multiple layers or sequential transformations, creating the effect of a story that unfolds through interaction rather than text. While these works do not conform to traditional book formats, they function in many ways like miniature mechanical narratives, bridging the gap between printed ephemera and the broader history of movable and interactive books. Sliggers notes that many of these objects lack a formal publisher’s imprint, and instead bear abbreviated or initial-based marks—such as ‘A.N. Paris’ or ‘P.C. Paris’—which appear to function as minimal identifiers rather than conventional publishing statements.
And then there’s the question of survival. Or rather—lack of it. Sliggers makes it clear that institutions largely ignored, rejected, or even destroyed this material. Libraries didn’t catalog it. Museums didn’t display it. In some cases, confiscated items were simply eliminated. What remains today survives mostly because collectors held onto it—quietly, privately, often outside the official record.
That’s why these objects keep turning up in auctions and private collections, while barely appearing in traditional histories. They sit in this strange space—clearly part of the history of paper engineering, clearly using the same mechanical principles as movable books—but operating just outside the boundaries of what was considered acceptable, collectible, or even worth preserving.
What Sliggers ultimately reveals is not just a hidden category of erotica, but a parallel history of interactive print. Same ingenuity. Same fascination with movement and transformation. Just applied to material that, for a long time, had to stay one step ahead of being seen.
"Global Map" of censored paper engineering:
The Kinsey Institute Library at Indiana University holds a significant body of nineteenth-century erotic material, including novelty objects and paper mechanisms, much of which remains underdocumented or not widely digitized—suggesting that the full extent of these interactive formats is still not completely understood.
The Enfer (literally “Hell” or “Inferno”) is a restricted collection within the Bibliotheque nationale de France dedicated to erotic, pornographic, and otherwise prohibited materials, including movable works. Within this context, movable books were often considered among the most transgressive objects, as their meaning depended upon physical interaction. The act of lifting a flap or opening a concealed element to reveal an image was, in the eyes of nineteenth-century authorities, more provocative than a static illustration, as it required the viewer’s direct participation in the act of revelation.
The collection was formally established between 1836 and 1844 during a period of increasing social regulation and moral scrutiny, with the aim of restricting access to works deemed harmful to public decency. Many items entered the collection through police confiscation, legal seizure of illicit publications, and, in some cases, private donations. The “Enfer” press mark itself was closed in 1969 but later reinstated in 1983 for organizational purposes.
In 2007, the Bibliotheque nationale de France mounted its first major public exhibition of these materials, Eros au secret, allowing broader—though still controlled—access to works that had long been withheld from public view. Today,some of the collection has been digitized and made accessible through Gallica, the library’s online portal, offering unprecedented access to materials once considered too sensitive for general readership. See https://gallica.bnf.fr/conseils/content/enferFor a deeper exploration of this material, the Bibliotheque nationale de France publication L’Enfer de la Bibliotheque nationale offers a detailed study of the collection and its historical context. The Bibliotheque also published a definitive, illustrated catalog for its landmark exhibition, L’Enfer de la Bibliotheque: Eros au secret. For more information, see the exhibition publication and related materials available through https://editions.bnf.fr/lenfer-de-la-bibliotheque
The Private Case of the British Library is a restricted collection of erotic printed works, transferred from the British Museum in 1973 and broadly comparable in purpose to the Enfer at the Bibliotheque nationale de France. Established in the mid-nineteenth century, it was used to segregate material deemed obscene or otherwise unsuitable for general access. The Victorian bibliophile Henry Spencer Ashbee (1834–1900), writing under the pseudonym Pisanus Fraxi, remains one of the most important early bibliographers of erotic literature. His three major works—Index Librorum Prohibitorum, Centuria Librorum Absconditorum, and Catena Librorum Tacendorum—continue to serve as foundational references for identifying rare nineteenth-century erotic material. Ashbee’s substantial collection, comprising thousands of volumes including a significant body of erotic works, helped form a major component of what became known as the Private Case.
The Phi (Φ) collection at the Bodleian Library, Oxford, serves as the university’s counterpart to the British Library’s “Private Case.” Established in 1882 under head librarian E.W.B. Nicholson, it functioned as a restricted classification for “improper” books, allowing the library to comply with legal deposit requirements while limiting access to sexually explicit or socially subversive material. Comprising several thousand items, the collection includes numerous small-format volumes and pamphlets incorporating folding plates, hidden imagery, and other mechanical features. While the Phi collection houses bound works, the Bodleian’s John Johnson Collection of Printed Ephemera contains a substantial body of related trade novelties, and the boundary between the two is often fluid: a mechanical erotic card might reside in the Johnson archive, while a book containing that same device would be assigned a Phi shelfmark.
In practice, the Φ designation functioned as both a physical and symbolic barrier, diverting material from general circulation on the basis not only of subject matter but of function—particularly when pull-tabs, flaps, or other movable elements revealed imagery deemed “obscene.” Although this classification restricted access, it also had the unintended effect of preserving fragile nineteenth-century paper mechanisms. By sequestering these objects from regular handling, the Phi collection effectively created a protected archive of delicate interactive formats, even as it removed them from mainstream bibliographical visibility for more than a century.
Unlike the formalized restricted classifications of the Bodleian’s Φ collection and the British Library’s Private Case, the United States developed a far less centralized approach to the control of “obscene” material. The so-called “Delta Collection” at the Library of Congress represents a lesser-known American parallel, though it operated in a more informal and only partially documented manner. As described in internal records and later scholarship, the collection consisted largely of materials deemed obscene, many of which entered the Library through seizures by the U.S. Customs Service and the Post Office under federal censorship laws.
Unlike its European counterparts, the Delta Collection was not publicly catalogued and appears to have been referenced primarily in unpublished institutional reports, contributing to its relative obscurity. Its holdings likely included a wide range of ephemeral and imported materials—printed novelties, small-format objects, and items incorporating simple paper mechanisms such as flaps, sliders, and concealed imagery—suggesting that interactive and often erotic formats circulated more widely than surviving catalogued collections might indicate. What remains points to a parallel history of paper engineering in the United States that survives only in fragments—scattered, underdocumented, and only partially visible within major institutional holdings.
References:
Ashbee, Henry Spencer (Pisanus Fraxi).Index Librorum Prohibitorum: Being Notes Bio-Biblio-Icono-Graphical and Critical on Curious and Uncommon Books. London, 1877.
Beisel, Nicola Kay.
Imperiled Innocents: Anthony Comstock and Family Reproduction in Victorian America. Princeton: Princeton University Press, 1997.
Colonna, Francesco.
Hypnerotomachia Poliphili: The Strife of Love in a Dream. Translated by Joscelyn Godwin. London: Thames & Hudson, 1999. First published Venice: Aldus Manutius, 1499.
Doosry, Yasmin.
Käufliche Gefühle: Zur Kultur der Liebesgaben im Biedermeier. Munich: Deutscher Kunstverlag, 2004.
Gertzman, Jay A.
Bookleggers and Smuthounds: The Trade in Erotica, 1920–1940. Philadelphia: University of Pennsylvania Press, 1999.
Horowitz, Maryanne. “The Keeper of the Collections and the Delta Collection: Regulating Obscenity at the Library of Congress, 1940–1963.”
eScholarship, University of California. https://escholarship.org
Kearney, Patrick J.
The Private Case: An Annotated Bibliography of the Private Case Erotica Collection in the British (Museum) Library. London: Jay Landesman, 1981.
Kendrick, Walter.
The Secret Museum: Pornography in Modern Culture. New York: Viking, 1987.
Quignard, Marie-Françoise, and Raymond-Josué Seckel, eds.
L’Enfer de la Bibliothèque: Éros au secret. Paris: Bibliothèque nationale de France, 2007. Exhibition catalog, Bibliothèque nationale de France, December 4, 2007–March 2, 2008.
Schmidt, Suzanne Karr.
Interactive and Sculptural Printmaking in the Renaissance. Leiden: Brill, 2018.
Sigel, Lisa Z.
Governing Pleasures: Pornography and Social Change in England, 1815–1914. New Brunswick, NJ: Rutgers University Press, 2002.
Sliggers, Bert.
Vouwen, klappen, trekken, draaien: Pornografisch drukwerk voor de ongeletterde [Folding, Flipping, Pulling, Turning: Pornographic Printed Matter for the Illiterate]. Zutphen: Walburg Pers, 2023.
