List of sources:
Cape of Good Hope. Civil service list, 1910.
Charles Leopold Layard Biden. Geni. Retrieved on 18 August 2023 from https://www.geni.com/people/Charles-Biden/6000000038109100641
FamilySearch. Charles Leopold Layard Biden. Retrieved on 18 August 202 from https://www.familysearch.org/ark:/61903/1:1:6N7L-Z1NJ and https://www.familysearch.org/ark:/61903/1:1:6XLF-XBHP and https://www.familysearch.org/ark:/61903/1:1:D921-ZTMM and https://www.familysearch.org/ark:/61903/1:1:DZQ6-L22M
My Heritage. www.myheritage.com/names/charles_biden
National Archives Repository, Pretoria (TAB). Source MHG, Reference 2653/63. Estate documents, Charles Leopold Layard Biden.
National Automated Archival Information Retrieval System (NAAIRS). http://www.national.archives.gov.za/naairs.htm Documents relating to Charles Leopold Layard Biden / C.L.L. Biden.
Obituary: Charles Leopold Layard Biden (1884-1963). News Bulletin of the Zoological Society of South Africa, 1963, Vol. 4(3), pp. 53-54.
Retrospective South African national bibliography for the period 1926-1958. Pretoria: State Library, 1985.
Union of South Africa. Public service list, 1914.