APA (7th ed.) Citation

Stewart, I. (1993). Testing hypotheses. New Scientist, 140, 4.

Chicago Style (17th ed.) Citation

Stewart, Ian. "Testing Hypotheses." New Scientist 140 (1993): 4.

MLA (9th ed.) Citation

Stewart, Ian. "Testing Hypotheses." New Scientist, vol. 140, 1993, p. 4.