Cita APA (7a ed.)

Zimmermann, P. (1996). The official PGP user's guide. MIT.

Cita Chicago Style (17a ed.)

Zimmermann, Philip. The Official PGP User's Guide. Cambridge (Massachusetts) [etc.]: MIT, 1996.

Cita MLA (9a ed.)

Zimmermann, Philip. The Official PGP User's Guide. MIT, 1996.