Oldenburger, Jesper, and Bert Theunissen. “Alexander Numan (1780-1852) En De Veredeling Van De Nederlandse Schapenrassen”. Studium 8, no. 2 (October 13, 2015): 65–83. Accessed April 11, 2026. https://testplatform.openjournals.nl/studium/article/view/20371.