by Guffy, R.D, Vanden Heuvel, R.M, Vasilas, B.L, Nelson, R.L, Frobish, M.A, Hesketh, J.D
Published in Soil biology & biochemistry (1989)

by Shoemaker, R.C, Guffy, R.D, Lorenzen, L.L, Specht, J.E
Published in Crop science (01.09.1992)

by Guffy, R.D., Vanden Heuvel, R.M., Vasilas, B.L., Nelson, R.L., Frobish, M.A., Hesketh, J.D.
Published in Soil biology & biochemistry (1989)

by Egli D.B, Guffy R.D, Leggett J.E
Published in Agronomy journal (01.01.1985)

by Egli, D.B. (Kentucky Univ., Lexington (USA). Dept. of Agronomy), Guffy, R.D, Heitholt, J.J
Published in Journal of agronomy and crop science (1986) (01.09.1987)

by Egli, D.B, Guffy, R.D, Meckel, L.W, Leggett, J.E. (Dep. of Agron., Kentucky Univ., Lexington, KY 40546 (USA))
Published in Annals of Botany (UK) (1985)