Keywords: Mittelholzer Zoo 1930.jpg Zoo Zürich 1930 Aufnahme von Walter Mittelholzer 1894 - 1937 Die Schweiz von damals Flugaufnahmen von Walter Mittelholzer Weltbild-Verlag Olten 2005 1930 upload Dezember 2008 Walter Mittelholzer upload by Adrian Michael Aerial photographs of Zürich Walter Mittelholzer Zürich Zoo PD-old Swiss copyright on Mittelholzer's work's expired at the end of 1987 since Switzerland had a copyright term of 50 years p m a until 1993 and the extension to 70 years p m a made in 1993 did not restore already expired copyrights 1930 in Switzerland |