Autore:Frederick Soddy

  1. 1,0 1,1 Encyclopædia Britannica
  2. 2,0 2,1 SNAC
  3. 3,0 3,1 Brockhaus Enzyklopädie
  4. 4,0 4,1 Store norske leksikon
  5. 5,0 5,1 Bibliothèque nationale de France
  6. Grande Enciclopedia Sovietica 1969–1978