by Nicol, C. J., Davidson, H.P. D., Harris, P. A., Waters, A. J., Wilson, A. D.
Published in Veterinary record (30.11.2002)

by Reimers T.J, Cowan R.G, Davidson H.P, Colby E.D
Published in American journal of veterinary research (1981)

by Davidson, H P, Rebhun, W C, Habel, R E
Published in Cornell Veterinarian (1981)