TY - Generic T1 - Differential effects of ammonium nitrate on three heathland species Y1 - 1998 A1 - De Graaf, M.C.C. A1 - Bobbink, R. A1 - Roelofs, J.G.M. A1 - Verbank, P.J.M. JF - Plant Ecology VL - 135 ER - TY - Generic T1 - Distribution and decline of endangered herbaceous heathland species in relation to the chemical composition of the soil Y1 - 1993 A1 - Houdijk, A.L.F.M. A1 - Verbank, P.J.M. A1 - van Dijk, H.F.G. A1 - Roelofs, J.G.M. JF - Plant and Soil VL - 148 ER -