H R Guilbert, A Wahid, K A Wagnon, P W Gregory: Observations on pigmentation of eyelids of Hereford cattle in relation to occurrence of ocular epitheliomas. In: Journal of Animal Science. Band7, Nr.4, 1. November 1948, S.426–9, doi:10.2527/1948.74426x (oup.com [abgerufen am 16. Dezember 2021]).
H R Guilbert, A Wahid, K A Wagnon, P W Gregory: Observations on pigmentation of eyelids of Hereford cattle in relation to occurrence of ocular epitheliomas. In: Journal of Animal Science. Band7, Nr.4, 1. November 1948, S.426–9, doi:10.2527/1948.74426x (oup.com [abgerufen am 16. Dezember 2021]).