Let us draw your attention to a work of Dimitris E. Bakaloudis, Christos G. Vlachos and Graham J. Holloway on Short-toed Eagle in northeast Greece /map/:
• D.E. Bakaloudis, C.G. Vlachos, G.J. Holloway, 2005 – Nest spacing and breeding performance in Short-toed Eagle Circaetus gallicus in northeast Greece // British Trust for Ornithology, Bird Study, 52: 330–338. – 
(En).
This text can be found on the Taylor & Francis Online website.