Vladimir Ivanovski & Dimitris E. Bakaloudis’ works
See the photo located on the Birdlife Belarus website and some links to V. Ivanovski‘s works concerning Short-toed Eagle ecology in Nothern Belarus /map/ (all contain summaries in English):
• В. Ивановский, 1992 – Экология гнездования змееяда в Белорусском Поозерье // Современная орнитология: 56-69. – 
(Ru) (translatable form)
(source – website of the Working Group on Raptors of Northern Eurasia).
• В. Ивановский, 2002 – Змееяд в Северной Беларуси: настоящее и будущее // Беркут, 11 (2): 158-164. – (Ru) (translatable form)
(source – website of the Ukrainian journal of ornithology BERKUT). The summary of this work can be found on the World Working Group on Birds of Prey and Owls website: The Short-toed Eagle Circaetus gallicus in Belarus (En) – sixth article. At the same time mark the first article on the list also, that is an abstract of the oral report of another researcher: Dimitris E. Bakaloudis – Aspects of the Ecology of the Short-toed Eagle Circaetus gallicus in Dadia Soufli Forest, NE Greece (En) /map/.