@article {609, title = {Effects of atmospheric ammonia and ammonium sulphate on vesicular-arbuscular mycorrhizal colonisation in three heathland species}, journal = {New Phytologist}, volume = {127}, year = {1994}, pages = {685-696}, author = {Heijine, B. and Dueck, T.A. and Van der Eerden, L.J.M. and Heil, G.} }