APA (7th ed.) Citation

Hoare, C. (1989). The Varieties of Programming Language. Springer.

Chicago Style (17th ed.) Citation

Hoare, C. The Varieties of Programming Language. Springer, 1989.

MLA (9th ed.) Citation

Hoare, C. The Varieties of Programming Language. Springer, 1989.

Warning: These citations may not always be 100% accurate.