Alcover, Josep Antoni (1989): Les Aus fòssils de la Cova de Ca Na Reia. Endins14-15: 95-100. [In Catalan with English abstract]
Ballmann, Peter (1969): Les Oiseaux miocènes de la Grive-Saint-Alban (Isère) [The Miocene birds of Grive-Saint-Alban (Isère)]. Geobios2: 157-204. [French with English abstract] doi:10.1016/S0016-6995(69)80005-7 (HTML abstract)
Brodkorb, Pierce (1964): Catalogue of Fossil Birds: Part 2 (Anseriformes through Galliformes). Bulletin of the Florida State Museum8(3): 195-335. PDF or JPEG fulltext
Cracraft, Joel (1969): Notes on fossil hawks (Accipitridae). Auk86(2): 353-354. PDF fulltext
Mlíkovský, Jirí (2002): Cenozoic Birds of the World, Part 1: Europe. Ninox Press, Prague. OCLC156629447. PDF fulltext
Wetmore, Alexander (1933): Status of the Genus Geranoaëtus. Auk50(2): 212. DjVu fulltextPDF fulltext