This old paper, dedicated to study of Short-toed Eagle diet in the Capanne di Marcarolo Natural Regional Park /map/ at the end of XX century, is available on the Carmagnola Natural History Museum site:
• Massimo CAMPORA, Silvia ALBERTI, 1997 – Osservazioni sulla dieta del biancone (Circaetus gallicus) in un’area dell’Appennino settentrionale [Observations on Short-toed Eagle diet in Northern Appennines (Italy, NW)] // Rivista Piemontese di Storia Naturale, 18: 233-239. – 
(It).
Currently, you can find online full texts of these two articles published in scientific journals in 2004 and 2005. The papers have already been mentioned on our site before:
• Paola SACCHI, Dominga SOGLIA, Sandra MAIONE, Giuseppe MENEGUZ, Massimo CAMPORA, Roberto RASERO, 2004 – A non-invasive test for sex identification in Short-toed Eagle (Circaetus gallicus) // Molecular & Cellular Probes, 18 (3): pp. 193-196. – (En).
• Massimo CAMPORA, Guido CATTANEO, 2005 – Ageing and sexing Short-toed Eagles // British Birds, 98: pp. 370-376. – (En).
This is just selection of links on miscellaneous texts and abstracts of articles about Short-toed Eagles. So…
Some abstracts can be found on the NCBI website with PubMed database:
• Sacchi P, Soglia D, Maione S, Meneguz G, Campora M, Rasero R, 2004 – A non-invasive test for sex identification in short-toed Eagle (Circaetus gallicus) // Mol Cell Probes, Jun 18 (3): 193-6. (En).
• Martin GR, Katzir G, 1999 – Visual fields in Short-toed Eagles, Circaetus gallicus (Accipitridae), and the function of binocularity in birds // Brain Behav Evol, 53 (2): 55-66. (En).
The encyclopedic compilation of information (Es) among other things has extensive ornithological bibliography concerning researching of Short-toed Eagle. The source is a site of the Enciclopedia Virtual de los Vertebrados Españoles.