BioStor
 | New races of the genus Otus from northwestern Mexico R T Moore (1937) Proceedings of The Biological Society of Washington 50: 63-68 |
 | Birds of Tikal, Guatemala, by Frank B. Smithe and Raymond A. Paynter, Jr F B Smithe and R A Paynter (1953) Bulletin of The Museum of Comparative Zoology 128: 245-324 |