MLA

Yale Peruvian Expedition ($d: 1911). Notebooks. Box 21, folder 39. 1914-1915. https://collections.library.yale.edu/catalog/33346946.

APA, 6th edition

Yale Peruvian Expedition ($d: 1911). (["Box 21, folder 39"])(1914-1915)[Notebooks]. https://collections.library.yale.edu/catalog/33346946.