Commodore 64 Type-In Program Books - Information and screenshots of type-in games found in dozens of Commodore 64 programming books. Part of the Gamebase64 collection. - http://www.btinternet.com/~pweighill/music/books/
Commodore Related Books & Magazines - Personal collection of Amiga and Commodore 64 books and manuals with descriptions. - http://roger.trideja.com/books/
AtariArchives.org - Full text of various computer books from the 1980s including a few respected Commodore titles like "Machine Language For Beginners" and its sequel. - http://www.atariarchives.org/