Cita APA (7a ed.)

Costales, B., & Allman, E. (2002). Sendmail (3rd ed.). O'Reilly.

Cita Chicago Style (17a ed.)

Costales, Bryan, y Eric Allman. Sendmail. 3rd ed. Beijing: O'Reilly, 2002.

Cita MLA (9a ed.)

Costales, Bryan, y Eric Allman. Sendmail. 3rd ed. O'Reilly, 2002.