William_E._and_Joy_R._Drohan_[[editors]]_Sharpe_(The_Effects_of_Acidic_Deposition_on_Pennsyvania's_Forests._Volume_1:_Proceedings_of_the_1988_Pennsylvania_Acidic_Deposition_Conference,_September_14-16,_1998,_The_Pennsylvania_State_University,_University_Park,_PA.)