APA (7th ed.) Citation

Gries, D., & Levin, G. (1979). A procedure call proof rule: (with a simple explanation).

Chicago Style (17th ed.) Citation

Gries, David, and Gary Levin. A Procedure Call Proof Rule: (with a Simple Explanation). Ithaca, New York, 1979.

MLA (9th ed.) Citation

Gries, David, and Gary Levin. A Procedure Call Proof Rule: (with a Simple Explanation). 1979.