APA (7th ed.) Citation

Costales, B., Allman, E., & Rickert, N. (1997). Sendmail: [help for UNIX system administrators] (2. ed., rev. & updated.). O'Reilly.

Chicago Style (17th ed.) Citation

Costales, Bryan, Eric Allman, and Neil Rickert. Sendmail: [help for UNIX System Administrators]. 2. ed., rev. & updated. Cambridge [u.a.]: O'Reilly, 1997.

MLA (9th ed.) Citation

Costales, Bryan, et al. Sendmail: [help for UNIX System Administrators]. 2. ed., rev. & updated. O'Reilly, 1997.