This is one more article from the Ardeola website:
• IRIBARRER, J.J. and RODRÍGUEZ-ARBELOA, A.., 1973 – Observaciones en un nido del Águila Culebrera (Circaetus gallicus), Navarra 1972 [Observations on a nest of Short-toed Eagle, Navarra 1972] // Ardeola 19(1), 101-106. – 
(Es) /map/.
The text was published in 1973 including some black-and-white images. The placed PDF file is not of the best quality, but it’s fairly readable.
Just the translatable text form for two articles (Ru) of Vladimir Ivanovski /map/ is meant now:
• В. Ивановский, 1992 – Экология гнездования змееяда в Белорусском Поозерье [Ecology of Short-toed Eagle nesting in the Byelorussian Poozerje] // Современная орнитология: 56-69.
• В. Ивановский, 2002 – Змееяд в Северной Беларуси: настоящее и будущее [Short-toed Eagle in Northern Belarus: present and future] // Беркут, 11 (2): 158-164.