BIELEMAN , J. (n.d.). Rural Change in the Dutch Province of Drenthe in the Seventeenth and Eighteenth Centuries. British Agricultural History Society. https://www.bahs.org.uk/AGHR/ARTICLES/33n2a1.pdf
Porter, V., & Mason, I. L. (2002). Mason’s World Dictionary of Livestock Breeds, Types and Varieties (5th ed.). Wallingford, Oxfordshire, UK: CABI Publishing.
Porter, V., Alderson, L., Hall, S. J. G., & Sponenberg, D. P. (2016). Mason’s World Encyclopedia of Livestock Breeds and Breeding: 2 Volume Pack (1st ed.). Wallingford, Oxfordshire, UK: CABI.
United States. Bureau of Foreign Commerce. (1888). Cattle and Dairy Farming, Part 2. U.S. Government Printing Office.