Note 55 — BULLETIN OF THE NUTTALL ORNITHOLOGICAL CLUB. VOL. VII. April, 1882. No. 2. (continued 2)
Reading edition
Dr. C. Fr. W. Krukenberg. Die Farbstoffe der Federn, in Dessen Vergleichendphysiologische Studien. I Reihe, V Abth., 1881, s. 72–92. Plate III.