Didn't the angels sing
MLA
Didn't the Angels Sing. Leo Feist, Inc., 0AD. https://collections.library.yale.edu/catalog/2011980.
APA, 6th edition
Didn't the angels sing. (0 C.E.). [Musical works, Sheet music, Sheet music covers]. Leo Feist, Inc. https://collections.library.yale.edu/catalog/2011980.