Rupela, O P and Kumar Rao, J V D K and Wani, S P and Johansen, C, eds.  (1994) Linking Biological Nitrogen Fixation Research in Asia: report of a meeting of the Asia Working Group on Biological Nitrogen Fixation in Legumes 6-8 Dec 1993.    International Crops Research Institute for the Semi-Arid Tropics.  ISBN 9290662972