Plant-soil interactions at Low pH : Proceedings of the Second International Symposium on Plant-Soil Interactions at Low pH, 24-29 June 1990, Beckley, West Virginia, USA / Edited by Robert J. Wright, V.C. Baligar, R. Paul Murrmann. - Wright, R. J.; Wright, R. J.; Baligar, V.C; Murrman, R.P (Kluwer Academic Publishers, 1991)