@article {1119, title = {Differential effects of nitrate and ammonium on three fen bryophyte species in relation to pollutant nitrogen input.}, journal = {New Phytologist}, volume = {164}, year = {2004}, pages = {451-458}, author = {Paulissen, M.P.C.P. and van der Ven, P.J.M. and Dees, A.J. and Bobbink, R.} }