This text (Uk) written by eminent Ukrainian expert on Raptors V. M. Zubarovski is extracted from his monograph which in whole was dedicated to Raptors of Ukraine and included some black-and-white photos:
• Зубаровський В. М., 1977 – Хижі птахи (Фауна України; T.5. Вип. 2.). – К.: Наук. думка, 332 с.