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AGRIS: Food and Agriculture Organization of the United Nations. The entomologist B.W. Westermann... Retrieved on 3 May 2021 from https://agris.fao.org/agris-search/search.do?recordID=XE8021635
Ffolliott, P. & Liversidge, R. Carl Heinrich Bergius, Cape apothecary and collector, 1816-1818. Quarerly Bulletin of the South African Library, 1964, Vol. 18, pp. 134-142 and 183-192.
Google scholar. http://scholar.google.co.za/
National Automated Archival Information
Retrieval System (NAAIRS). http://national.archives.gov.za/naairs.htm Documents relating to BW Westerman,
Royal Society of London. Catalogue of scientific papers [1800-1900]. London: Royal Society, 1867-1925.