Cita APA (7th ed.)

Chellas, B. F. (1980). Modal Logic: An introduction. C. U. Pr..

Cita Chicago (17th ed.)

Chellas, Brian F. Modal Logic: An Introduction. Cambridge: C. U. Pr., 1980.

Cita MLA (9th ed.)

Chellas, Brian F. Modal Logic: An Introduction. C. U. Pr., 1980.