Cite

Letters of introduction

MLA

Yale Peruvian Expedition ($d: 1911). Letters of introduction. Box 1, folder 21. 1911. https://collections.library.yale.edu/catalog/10014096.

APA, 6th edition

Yale Peruvian Expedition ($d: 1911). (["Box 1, folder 21"])(1911)[Letters of introduction]. https://collections.library.yale.edu/catalog/10014096.