List of sources:
Cape of Good Hope. Report of the South African Museum for the years ... 1910, 1911, 1912.
Geological Society of South Africa. Transactions (and Proceedings), 1915, Vol. 18, list of members.
Hall, A.L. A bibliography of South African geology.... Pretoria: Geological Survey, Memoirs No. 18 (1922), 25 (1927), 27 (1931), and 30 (1937).
Hillebrecht, W. Unpublished notes for a Dictionary of Namibian biography. National Archives of Namibia, 25 June 2004.
Hoal, B.G., Hugo, P.J. & Schalk, K.E.L. Geological survey of Namibia. In C.R. Anhaeusser (ed.), A century of geological endeavour in southern Africa, 1895-1995 (pp. 358-365). Johannesburg: Geological Society of South Africa, 1997.
Hugo, P.J., Schalk, K.E.L. & Barnes, S.J. Bibliography of South West African/Namibian earth science. Windhoek: Geological Survey, 1983.
Logan, R.F. Bibliography of South West Africa, Geography and related fields. Windhoek: SWA Scientific Society, 1969.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to H. Lotz.
National Union Catalogue, pre-1956 imprints. London: Mansell, 1968-1980.
Royal Society of London. Catalogue of scientific papers [1800-1900]. London: Royal Society, 1867-1925.
Royal Society of South Africa. Transactions, 1908-1910, Vol. 1 and 1917, Vol. 6: Lists of members.
Schneider, G.I.C. The
history of the Geological Survey of Namibia. Communications of the Geological Survey of Namibia, 2000, Vol. 12,
pp. 1-14.