Não informado. Polled Hereford World. American Polled Hereford Association.
Chicago-viite (17. p.)Não informado. Polled Hereford World. Kansas City, Kan: American Polled Hereford Association.
MLA-viite (8. p.)Não informado. Polled Hereford World. American Polled Hereford Association.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.