List of sources:
Medical, dental and pharmacy register for the Transvaal, 1907.
National Archives Repository (TAB), Source MHG, Vol. 0, Ref. 17215: death notice, Max Marcus Klein.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to Klein, Max Marcus / Klein, M.M.
South African medical directory for 1897. Cape Town: Cape Times, 1897.
South African Medical Record, 1903/4, Vol. 1.
Staats-almanak der Zuid-Afrikaansche Republiek, 1899, pp. 86-93, Naamlijst van de geadmitteerde genees-, heel- en verloskundigen.
Transvaal Medical Journal, 1908, Vol. 4.