@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},
	volume = {141},
	year = {1999},
	pages = {433-442},
	author = {Johnson, D. and Leake, J.R. and Lee, J.A.}
}
