MLA

McGlashan, E. L. (Everitt Lynn), 1911-1978. Martin, Jacob. Manumission document for a "Negro manservant named Boston," [Biddeford, Maine?] (M12). Box 1, folder 30. 1770 Aug 17. https://collections.library.yale.edu/catalog/33219773.

APA, 6th edition

McGlashan, E. L. (Everitt Lynn), 1911-1978. (["Box 1, folder 30"])(1770 Aug 17)[Martin, Jacob. Manumission document for a "Negro manservant named Boston," [Biddeford, Maine?] (M12)]. https://collections.library.yale.edu/catalog/33219773.