@article {801, title = {A Review of the Likely Causal Pathways Relating the Reduced Density of Breeding Dippers Cinclus-Cinclus to the Acidification of Upland Streams}, journal = {Environmental Pollution}, volume = {78}, year = {1992}, pages = {49-55}, author = {Tyler, S.J. and Ormerod, S.J.} } @article {1501, title = {Long-term change in the suitability of welsh streams for dippers Cinclus cinclus as a result of acidification and recovery: A modelling study.}, journal = {Environmental Pollution}, volume = {62}, year = {1989}, pages = {171-182}, author = {Ormerod, S.J. and Tyler, S.J.} }