MLA

Yale Peruvian Expedition ($d: 1911). Instructions for staff. Box 1, folder 14-19. 1911-1912. https://collections.library.yale.edu/catalog/10050617.

APA, 6th edition

Yale Peruvian Expedition ($d: 1911). (["Box 1, folder 14-19"])(1911-1912)[Instructions for staff]. https://collections.library.yale.edu/catalog/10050617.