TY - RPRT T1 - Biomonitoring methods for assessing the impacts of nitrogen pollution: refinement and testing Y1 - 2005 A1 - Leith, I. A1 - van Dijk, N. A1 - Pitcairn, C.E.R. A1 - Wolseley, P.A. A1 - Whitfield, C.P. A1 - Sutton, M.A. JF - JNCC PB - JNCC ER -