APA (7th ed.) Citation

De Castro Lopo, E., Aitken, P. G., & Jones, B. Sams teach yourself C Linux Programming in 21 days.

Chicago Style (17th ed.) Citation

De Castro Lopo, Erik, Peter G. Aitken, and Bradley Jones. Sams Teach Yourself C Linux Programming in 21 Days.

MLA (9th ed.) Citation

De Castro Lopo, Erik, et al. Sams Teach Yourself C Linux Programming in 21 Days.