Shapiro MD, Kronenberg Z, Li C, Domyan ET, Pan H, Campbell M, Tan H, Huff CD, Hu H, Vickrey AI, Nielsen SC, Stringham SA, Hu H, Willerslev E, Gilbert MT, Yandell M, Zhang G, Wang J. Genomic diversity and evolution of the head crest in the rock pigeon. Science. 2013 Mar 01; 339(6123):1063-7.