Terricolous lichens as indicators of nitrogen deposition: Evidence from national records.

Stevens, C.J.; Smart, S.M.; Henrys, P.A. ; Maskell, L.C. ; Crowe, A. ; Simkin, J. ; Cheffings, C.M. ; Whitfield, C. ; Gowing, D.J.G. ; Rowe, E.C. ; Dore, A.J.; Emmett, B.A.