Plymouth Rock chicken (English Wikipedia)

Y. Guo, M. Lillie, Y. Zan, J. Beranger, A. Martin, C. F. Honaker, P. B. Siegel, Ö. Carlborg (2019). A genomic inference of the White Plymouth Rock genealogy. Poultry Science. 98 (11): 5272–5280. doi:10.3382/ps/pez411.

fao.org (Global: 318^th place; English: 411^th place)

Transboundary breed: Plymouth Rock. Domestic Animal Diversity Information System of the Food and Agriculture Organization of the United Nations. Accessed October 2016.
Transboundary breed: Plymouth Rock Barred. Domestic Animal Diversity Information System of the Food and Agriculture Organization of the United Nations. Accessed October 2016.
Transboundary breed: Plymouth Rock White. Domestic Animal Diversity Information System of the Food and Agriculture Organization of the United Nations. Accessed October 2016.

Y. Guo, M. Lillie, Y. Zan, J. Beranger, A. Martin, C. F. Honaker, P. B. Siegel, Ö. Carlborg (2019). A genomic inference of the White Plymouth Rock genealogy. Poultry Science. 98 (11): 5272–5280. doi:10.3382/ps/pez411.

Plymouth Rock Chicken The Livestock Conservancy. Archived 10 October 2016.
APA Recognized Breeds and Varieties: As of January 1, 2012. American Poultry Association. Archived 4 November 2017.
Liste des races et variétés homologuée dans les pays EE (28.04.2013). Entente Européenne d’Aviculture et de Cuniculture. Archived 16 June 2013.
Breed Classification. Poultry Club of Great Britain. Archived 12 June 2018.
Dominique Chicken. Pittsboro, North Carolina: The Livestock Conservancy. Archived 26 January 2021.
New Study Determines Ancestry for White Plymouth Rock Chickens. Pittsboro, North Carolina: The Livestock Conservancy. Archived 29 September 2020.
Plymouth Rock Chicken. Pittsboro, North Carolina: The Livestock Conservancy. Archived 2 April 2023.