@article {512,
	title = {Observations on the changes in nitrate concentrations in seven upland moorland catchments in north eastern Scotland},
	volume = {27},
	year = {1993},
	pages = {1195-1199},
	author = {Black, K.E. and Lowe, J.A.H. and Billett, M.F. and Cresser, M.S.}
}
