Cita APA (7th ed.)

Klenk & Virginia. (2008). Understanding Symbolic Logic (5th ed.). Pearson Education India.

Cita Chicago (17th ed.)

Klenk i Virginia. Understanding Symbolic Logic. 5th ed. New Delhi: Pearson Education India, 2008.

Cita MLA (9th ed.)

Klenk i Virginia. Understanding Symbolic Logic. 5th ed. Pearson Education India, 2008.