Cita APA (7a ed.)

Smullyan, R. M. (1961). Theory of formal systems. Princeton University Press.

Cita Chicago Style (17a ed.)

Smullyan, Raymond M. Theory of Formal Systems. Princeton: Princeton University Press, 1961.

Cita MLA (9a ed.)

Smullyan, Raymond M. Theory of Formal Systems. Princeton University Press, 1961.