MLA

Ernest Augustus, King of Hanover, 1771-1851. [Don Giovanni. Excerpts]. Parts (2 cl (1 part), spt, trbn). Manuscript. Box 248, folder 1304. undated. https://collections.library.yale.edu/catalog/10000233.

APA, 6th edition

Ernest Augustus, King of Hanover, 1771-1851. (["Box 248, folder 1304"])(undated)[[Don Giovanni. Excerpts]. Parts (2 cl (1 part), spt, trbn). Manuscript]. https://collections.library.yale.edu/catalog/10000233.