MLA

Trudeau, G. B., 1948-. Doonesbury. Box 1989. 1989 May 30. https://collections.library.yale.edu/catalog/2053162.

APA, 6th edition

Trudeau, G. B., 1948-. (["Box 1989"])(1989 May 30)[Doonesbury]. https://collections.library.yale.edu/catalog/2053162.