@article {633, title = {The effects of quantity and duration of simulated pollutant nitrogen deposition on root-surface phosphatase activities in Calcareous and acid grasslands: a bioassay approach}, journal = {New Phytol}, volume = {141}, year = {1999}, pages = {433-442}, author = {Johnson, D. and Leake, J.R. and Lee, J.A.} }