List of sources:
FamilySearch: William Whittingdale. https://www.familysearch.org/en/tree/person/details/GTW3-RH1
Gill, D. A history and description of the Royal Observatory, Cape of Good Hope (Appendix 1). London: HSMO, 1913.
Google scholar. http://scholar.google.co.za/ , publications
by W. Whittingdale.
Journal of the Astronomical Society of South Africa, 1938, Vol. 4(3), pp. 135-137, Members and Associates.
Liebenberg, E. C. Die topografiese kartering van Suid-Afrika, 1879-1972; 'n histories-geografiese ontleding. MA-verhandeling in Geografie, Universiteit van Suid-Afrika.
Marsh, F. W. and Menzies, G. H. Requiem to W. Whittingdale. 1. As Director of Trigonometrical Survey, 1933-1945. 2. As Editor of the South African Survey Journal. South African Survey Journal, 1966, Vol. 10(5), pp. 304-308.
National Automated Archival Information
Retrieval System (NAAIRS). http://national.archives.gov.za/naairs.htm Documents relating to William Whittingdale / W. Whittingdale.
[Obituary]: Mr William Whittingdale. South African Survey Journal, 1966, Vol. 10, pp. 299-300.
Simpson, K. A history of the South African trigonometrical system. South African Journal of Surveying and Mapping, 1989, Vol. 20(3), pp. 109-119.
South African Survey Journal, 1923-1938, Vol. 1-5, articles by W. Whittingdale; office bearers.
University of the Cape of Good Hope. Calendar, 1917/8, Survey Certificate Examination.