APA (7th ed.) Citation

Hoel, P. G., & Port, S. (1991). Introduction to probability theory. Universal Books Stall.

Chicago Style (17th ed.) Citation

Hoel, Paul G., and Sidney Port. Introduction to Probability Theory. New Delhi: Universal Books Stall, 1991.

MLA (9th ed.) Citation

Hoel, Paul G., and Sidney Port. Introduction to Probability Theory. Universal Books Stall, 1991.