List of sources:
Geological Society of South Africa. Transactions, 1906, Vol. 10, list of members.
Hall, A.L. A bibliography of South African geology to the end of 1920. Pretoria: Geological Survey, Memoir No. 18, 1922.
Men of the times: Pioneers of the Transvaal and glimpses of South Africa. Johannesburg: Transvaal Publishing Co., 1905.
National Automated Archival Information Retrieval System (NAAIRS). http://national.archives.gov.za/naairs.htm Documents relating to Shepherd, Percy Gladstone.
Percy Gladstone Shepherd. Geni. Retrieved from https://www.geni.com/people/Percy-Shepherd/6000000091869136872 as on 6 October 2020.
Shepherd, P.G. The principles of geology as deduced from a study of the sedimentary formations in South Africa. London, 1897.
South African Association for the Advancement of Science. Report, 1903, 1905/6: Lists of members.
South African bibliography to the year 1925. London: Mansell, 1979.
South African who's who, 1908.