caption: Robert J. Evans, Red Rock. From Lynch, C. F. (1914). Diseases of swine, with particluar reference to hog-cholera. W. B. Saunders in the public domain.
Lynch, C. F., & White, G. R. (1914). Diseases of swine: With Particluar reference to hog-cholera. Philadelphia, PA: W. B. Saunders.
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.