Brenda Love, Michael Perry. 1994. The Encyclopedia of Unusual Sex Practices. Barricade Books Incorporated. ISBN 1569800111. (Web-versio (Arkistoitu – Internet Archive))
Brenda Love, Michael Perry. 1994. The Encyclopedia of Unusual Sex Practices. Barricade Books Incorporated. ISBN 1569800111. (Web-versio (Arkistoitu – Internet Archive))