9Eriksen J, Murphy M D, Schnug E. The soil sulphur cycle[A].In: Schnug, E. and Beringer, H. ( ed. ) : Sulphur in Agro -Ecosystems [ C ], Vol. 2 of the series Mineral Nutrition in Ecosystems. Kluwer Academic Publ. Dordrecht, 1998.39 - 73.
10Pasricha N S, Aulakh M S. India Sulphur in Agric[J]. 1991, (15) :17 - 23.