Cita APA (7a ed.)

Slagell, M. (2002). Sams teach yourself Ruby in 21 days (1st edition.). Sams.

Cita Chicago Style (17a ed.)

Slagell, Mark. Sams Teach Yourself Ruby in 21 Days. 1st edition. Indianapolis, Ind.: Sams, 2002.

Cita MLA (9a ed.)

Slagell, Mark. Sams Teach Yourself Ruby in 21 Days. 1st edition. Sams, 2002.