MLA

Palade, George E. Heart Rat Atrium Peripheral Atrial Granules. Yale University School of Medicine, 7AD. https://collections.library.yale.edu/catalog/15817898.

APA, 6th edition

Palade, G. E. (7 C.E.). Heart Rat atrium peripheral atrial granules [Transmission electron micrograph]. Yale University School of Medicine. https://collections.library.yale.edu/catalog/15817898.