TY - Generic T1 - Differential effects of nitrate and ammonium on three fen bryophyte species in relation to pollutant nitrogen input. Y1 - 2004 A1 - Paulissen, M.P.C.P. A1 - van der Ven, P.J.M. A1 - Dees, A.J. A1 - Bobbink, R. JF - New Phytologist VL - 164 ER -