APA (7th ed.) Citation

Porter, P. (1989). Possible worlds / Peter Porter. Oxford University Press.

Chicago Style (17th ed.) Citation

Porter, Peter. Possible Worlds / Peter Porter. Oxford: Oxford University Press, 1989.

MLA (9th ed.) Citation

Porter, Peter. Possible Worlds / Peter Porter. Oxford University Press, 1989.

Warning: These citations may not always be 100% accurate.