Negro, Juan J.; Bortolotti, Gary R.; Mateo, Rafael; García, Isabel M. (2009). "Porphyrins and pheomelanins contribute to the reddish juvenal plumage of black-shouldered kites". Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology153 (3): 296–299. doi:10.1016/j.cbpb.2009.03.013. பப்மெட்:19351566.
Negro, Juan J.; Pertoldi, Cino; Randi, Ettore; Ferrero, Juan J.; López-Caballero, José M.; Rivera, Domingo; Korpimäki, Erkki; Boal, Clint (2006-09-01). "Convergent evolution of Elanus kites and the owls". Journal of Raptor Research40 (3): 222–225. doi:10.3356/0892-1016(2006)40[222:ceoeka]2.0.co;2. பன்னாட்டுத் தர தொடர் எண்:0892-1016.
Negro, Juan J.; Bortolotti, Gary R.; Mateo, Rafael; García, Isabel M. (2009). "Porphyrins and pheomelanins contribute to the reddish juvenal plumage of black-shouldered kites". Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology153 (3): 296–299. doi:10.1016/j.cbpb.2009.03.013. பப்மெட்:19351566.
Negro, Juan J.; Pertoldi, Cino; Randi, Ettore; Ferrero, Juan J.; López-Caballero, José M.; Rivera, Domingo; Korpimäki, Erkki; Boal, Clint (2006-09-01). "Convergent evolution of Elanus kites and the owls". Journal of Raptor Research40 (3): 222–225. doi:10.3356/0892-1016(2006)40[222:ceoeka]2.0.co;2. பன்னாட்டுத் தர தொடர் எண்:0892-1016.