(en) J. Ian H. Allonby, Philippe B. Wilson (éditeurs), British Poultry Standards: complete specifications and judging points of all standardized breeds and varieties of poultry as compiled by the specialist breed clubs and recognised by the Poultry Club of Great Britain, seventh edition. Chichester; Hoboken, New Jersey: Wiley Blackwell, (lire en ligne), p. 371 (ISBN9781119509141).
(en) J. Ian H. Allonby, Philippe B. Wilson (éditeurs), British Poultry Standards: complete specifications and judging points of all standardized breeds and varieties of poultry as compiled by the specialist breed clubs and recognised by the Poultry Club of Great Britain, seventh edition. Chichester; Hoboken, New Jersey: Wiley Blackwell., (lire en ligne), p. 5 (ISBN9781119509141).