Peiró, I. G., and E. Pagani-Núñez. “Plumage Colouration Variability of Male Bluethroats (Luscinia Svecica Cyanecula) Wintering in SE Iberia”. Ornis Fennica, vol. 93, no. 2, July 2016, pp. 111–120, doi:10.51812/of.133893.