MLA

Ernest Augustus, King of Hanover, 1771-1851. A Grand Sonata Dedicated to the Queen by Ignace Pleyel. Parts (5 cl, 2 bn, spt, 2 hn, trbn). Print (London: W. Milhouse). Box 197, folder 1008-1009. undated. https://collections.library.yale.edu/catalog/10000232.

APA, 6th edition

Ernest Augustus, King of Hanover, 1771-1851. (["Box 197, folder 1008-1009"])(undated)[A Grand Sonata Dedicated to the Queen by Ignace Pleyel. Parts (5 cl, 2 bn, spt, 2 hn, trbn). Print (London: W. Milhouse)]. https://collections.library.yale.edu/catalog/10000232.