Emlen, S. T. (1967). ‘Migratory orientation in the indigo bunting, passerina cyanea. Pt I: Evidence for use of celestial cues’, The Auk, 84 (3). P. 309–342. И: Emlen, S. T. (1967). ‘Migratory orientation in the Indigo Bunting, Passerina cyanea. Pt II: Mechanism of celestial orientation’, The Auk, 84 (4). P. 463–489.
