APA (7th ed.) Citation

Zimmermann, P. R. (1995). The official PGP user's guide (2. print.). MIT Press.

Chicago Style (17th ed.) Citation

Zimmermann, Philip R. The Official PGP User's Guide. 2. print. Cambridge, Mass. [u.a.]: MIT Press, 1995.

MLA (9th ed.) Citation

Zimmermann, Philip R. The Official PGP User's Guide. 2. print. MIT Press, 1995.