The represented article contains the detailed history of records of Short-toed Eagles in Switzerland almost within a century of observations:
• Kéry, M. & B. Posse, 1998 – Auftreten des Schlangenadlers Circaetus gallicus in der Schweiz von 1900 bis 1993 [Distribution of the Short-Toed Eagle in Switzerland from 1900 to 1993] // Der Ornithologische Beobachter, 95: 39-54. – 
(De).
This article was published about a quarter of a century ago. Now it is available on the Web, on a site of Oberösterreichisches Landesmuseum:
• Josef Reichholf, 1988 – Der Schlangenadler Circaetus gallicus in Bayern: Ein seltener aber regelmäßiger Durchzügler am Alpennordrand [The Short-toed Eagle in Bavaria: A Rare but Regular Migrant Along the Northern Fringe of the Alps] // Anzeiger der Ornithologische Gesellschaft in Bayern, 27 (1): 115-124. – (De) /map/.