W. J. Sollas. The Sagittal Section of the Human Skull. The Journal of the Royal Anthropological Institute of Great Britain and Ireland, [Royal Anthropological Institute of Great Britain and Ireland, Wiley], volume 63, pages 389-431, 1933. W. J. Sollas. On the cranial and facial characters of the neandertal race. Philosophical Transactions of the Royal Society of London. Series B, Containing Papers of a Biological Character, Royal Society, volume 199, issue 251261, pages 281-339, January 1908.