Ragnarock Productions: 21 Official "21" film site. Includes cast and crew credits, news regarding the film, and multimedia downloads. http://21themovie.com/home.htm

IMDb: 21 (2000) Cast and crew credits. Includes comments submitted by users. http://us.imdb.com/title/tt0224451/

IMDb: 20 Dates Crew and cast information, synopsis, trailer, and viewer comments. http://us.imdb.com/title/tt0138987/