APA (7th ed.) Citation

Higgins, P. J. (1971). Notes on categories and groupoids. Van Nostrand Reinhold.

Chicago Style (17th ed.) Citation

Higgins, Philip J. Notes on Categories and Groupoids. London, New York: Van Nostrand Reinhold, 1971.

MLA (8th ed.) Citation

Higgins, Philip J. Notes on Categories and Groupoids. Van Nostrand Reinhold, 1971.