%0 Generic %D 1991 %T Physiological-effects of long-term exposure to low concentrations of SO2 and NH3 on poplar leaves %A van Hove, L.W.A. %A Vankooten, O. %A Vanwijk, K.J. %A Vredenberg, W.J. %A Adema, E.H. %A Pieters, G.A. %B Physiologia Plantarum %V 82 %P 32-40