Gjershaug, J. O., H. R. L. Lerner, and O. H. Diserud. “Taxonomy and Distribution of the Pygmy Eagle Aquila (Hieraaetus) weiskei (Accipitriformes: Accipitridae)”. Zootaxa, vol. 2326, no. 1, Dec. 2009, pp. 24–38, doi:10.11646/zootaxa.2326.1.2.