1. Sten De Geer, Aftonbladets karta över Europa, Stockholm 1921, 2. edit. 1924. (Map with mfg. helt).
2. On the Definition, Method and Classification of Geography, Geografiska Annaler, Vol. V, Stockholm 1923.
3. Nordisk Världsatlas, Stockholm 1926, Map 45, Folkmangd (Population, world map with description by the author).
4. Albert Demangeon, La Picardie et les régions voisines, Paris, 3etirage 1925, page 311.
5. Malcolm Keir, Manufacturing Industries in America, New York 1920.