[40.] Osborn, H. F. Men of the Old Stone Age. New York, 1915.
[41.] Ranke, J. Der Mensch. Leipsic, 1900.
[42.] Geikie, J. Antiquity of Man in Europe. Edinburgh, 1914.
[43.] —— The Great Ice Age. 3d ed. London, 1894.
[44.] Reinhardt, L. Der Mensch zur Eiszeit in Europa. Munich, 1906.
[45.] Geikie, J. “Tundras and Steppes of Prehistoric Europe,” Smithson. Report, 1897-98, 321.
[46.] Nehring, A. Tundren u. Steppen der Jetzt-und Vor-zeit. Berlin, 1890.
[47.] Schöetensack, O. Der Unterkiefer des “Homo Heidelbergensis.” Leipsic, 1908.
[48.] MacCurdy, G. G. “The Eolith Problem,” Amer. Anth., N. S., VII, 1905, 425.
[49.] Sollas, W. J. Ancient Hunters. 2d ed. London, 1915.