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.
RYDER, M. L. (1981). A survey of European primitive breeds of sheep. Annales de Génétique et de Sélection Animale, 13(4), 381–418. https://doi.org/10.1051/gse:19810405