Magdeburg hemispheres. Multimedia Catalogue. Institute and Museum of the History of Science, Florence, Italy. 2006 [2012-07-04]. (原始内容存档于2010-08-09) (英语).美國國會圖書館的存檔,存档日期2010-08-09
Magdeburg hemispheres. Multimedia Catalogue. Institute and Museum of the History of Science, Florence, Italy. 2006 [2012-07-04]. (原始内容存档于2010-08-09) (英语).美國國會圖書館的存檔,存档日期2010-08-09