Journal in London (J 39-41)
MLA
Boswell, James, 1740-1795. Journal in London (J 39-41). Box 42, folder 988-89. 1775 Mar-Apr. https://collections.library.yale.edu/catalog/2039137.
APA, 6th edition
Boswell, James, 1740-1795. (["Box 42, folder 988-89"])(1775 Mar-Apr)[Journal in London (J 39-41)]. https://collections.library.yale.edu/catalog/2039137.