MLA

Tellefsen, Lisbet, 1961-. Aché buttons. Box 2, folder 93. undated. https://collections.library.yale.edu/catalog/32336916.

APA, 6th edition

Tellefsen, Lisbet, 1961-. (["Box 2, folder 93"])(undated)[Aché buttons]. https://collections.library.yale.edu/catalog/32336916.