APA (7th ed.) Citation

Ledgard, H. F., & Marcotty, M. (1981). The programming language landscape. Science Research Associates.

Chicago Style (17th ed.) Citation

Ledgard, Henry F., and Michael Marcotty. The Programming Language Landscape. Chicago: Science Research Associates, 1981.

MLA (9th ed.) Citation

Ledgard, Henry F., and Michael Marcotty. The Programming Language Landscape. Science Research Associates, 1981.