[1] Dubois, 1894. Pithecanthropus, ein Übergangsform, &c.
[2] Blanckenhorn, 1910. Zeitschrift für Ethnologie. Band 42, S. 337.
[3] Schwalbe, 1899. Zeitschrift für Morphologie und Anthropologie. From 1899 onwards.
[4] Berry, 1910. Proceedings of the Royal Society of Edinburgh, XXXI. Part 1. 1910.
[5] Cross, 1910. Proceedings of the Royal Society of Edinburgh, XXXI. Part 1. 1910.
[6] Schoetensack, 1908. Der Unterkiefer des Homo heidelbergensis.
[7] Keith, 1911. Lancet, March 18, 1911, abstract of the Hunterian Lectures.
[8] Dubois, 1896. Anatomischer Anzeiger. Band XII. S. 15.
CHAPTERS II AND III
[9] Avebury (Lubbock), 1868. International Congress for Prehistoric Archaeology.