The effect of air-borne ammonium sulphate onPinus nigra var.maritima in the Netherlands - Roelofs, J. G. M.; Kempers, A. J.; Houdijk, A. L. F. M.; Jansen, J. (Springer, 1985)
http://dx.doi.org/10.1007/BF02197866
Keywords: ZA-ZE