Armstrong, D. M. (1983). Whats is a law of nature. Cambridge University Press.
Cita Chicago (17th ed.)Armstrong, D. M. Whats Is a Law of Nature. Cambridge: Cambridge University Press, 1983.
Cita MLA (9th ed.)Armstrong, D. M. Whats Is a Law of Nature. Cambridge University Press, 1983.
Atenció: Aquestes cites poden no estar 100% correctes.