by Umberger, S.H. (Virginia Tech.)
Published in Virginia Cooperative Extension Service (USA) (1990)

by Umberger, S.H. (Virginia Tech.), Gerken, H.J. Jr
Published in Virginia Cooperative Extension Service (USA) (1992)

by Umberger, S.H. (Virginia Tech.), McKinnon, B.R, Eller, A.L. Jr
Published in Virginia Cooperative Extension Service (USA) (1991)