BioStor
 | Charles Vancouver Piper and the flora of the Pacific Northwest R K Beattie (1928) Proceedings of The Biological Society of Washington 41: 61-66 |
 | The song sparrow of San Miguel Island, California J Grinnell (1928) Proceedings of The Biological Society of Washington 41: 1-40 |
 | A list and index of the publications of the United States National Museum (1875–1946) Anon (1947) Bulletin of the United States National Museum 193: 1-306 |