MLA

Ernest Augustus, King of Hanover, 1771-1851. A Selection of the most admired and original German waltzes.... For harp or piano. Print (London: author). Box 583. 1806. https://collections.library.yale.edu/catalog/10000237.

APA, 6th edition

Ernest Augustus, King of Hanover, 1771-1851. (["Box 583"])(1806)[A Selection of the most admired and original German waltzes.... For harp or piano. Print (London: author)]. https://collections.library.yale.edu/catalog/10000237.