A2 Bg9 3 - A2 Mf4 Sh2
MLA
A2 Bg9 3 - A2 Mf4 Sh2. 1927. https://collections.library.yale.edu/catalog/2040510.
APA, 6th edition
A2 Bg9 3 - A2 Mf4 Sh2. (1927). [Annotations, Hand coloring, Lantern slides, Photographic prints, Photographs]. https://collections.library.yale.edu/catalog/2040510.