Citazione APA

Hughes, G. E., & Cresswell, M. J. (1972). An introduction to modal logic. Methuen.

Stile di citazione Chicago

Hughes, G. E., e M. J. Cresswell. An Introduction to Modal Logic. London: Methuen, 1972.

Citazione MLA

Hughes, G. E., e M. J. Cresswell. An Introduction to Modal Logic. Methuen, 1972.