Tolong jelaskan mengenai Klasifikasi dari Hentai

Buckley, Sandra (1991). "'Penguin in Bondage': A Graphic Tale of Japanese Comic Books", pp. 163–196, In Technoculture. C. Penley and A. Ross, eds. Minneapolis: University of Minnesota. .

McCarthy, Helen, and Jonathan Clements (1998). The Erotic Anime Movie Guide. London: Titan. .