MLA

Trudeau, G. B., 1948-. Doonesbury. Box 1987. 1987 April 28. https://collections.library.yale.edu/catalog/2053145.

APA, 6th edition

Trudeau, G. B., 1948-. (["Box 1987"])(1987 April 28)[Doonesbury]. https://collections.library.yale.edu/catalog/2053145.