@inbook {504, title = {Biological recording of changes in British wildlife}, volume = {ITE Symposium No. 20}, year = {1992}, publisher = {HMSO}, organization = {HMSO}, chapter = {Evidence for the effects of atmopheric pollution on bryophytes from national and local recording.}, address = {London}, author = {Adams, K.J. and Preston, C.D. and Harding, P.} }