Cita APA (7th ed.)

Copi, I. M., & Cohen, C. (1994). Introduction to logic. [s.n.].

Cita Chicago (17th ed.)

Copi, Irving M., i Carl Cohen. Introduction to Logic. Singapore: [s.n.], 1994.

Cita MLA (9th ed.)

Copi, Irving M., i Carl Cohen. Introduction to Logic. [s.n.], 1994.