Cita APA (7a ed.)

Doyle, R. (1994). Communicate with confidence. [s.n].

Cita Chicago Style (17a ed.)

Doyle, Robert. Communicate with Confidence. Time-Life bookS, AmSterdam: [s.n], 1994.

Cita MLA (9a ed.)

Doyle, Robert. Communicate with Confidence. [s.n], 1994.