Biological Nitrogen Fixation: Towards Poverty Alleviation through Sustainable Agriculture Proceedings of the 15th International Nitrogen Fixation Congress and the 12th International Conference of the African Association for Biological Nitrogen Fixation - Dakora, Felix D.; Dakora, Felix D.; Chimphango, Samson B. M.; Chimphango, Samson B. M.; Valentine, Alex J.; Valentine, Alex J.; Elmerich, Claudine.; Elmerich, Claudine.; Newton, William E.; Newton, William E. (Springer Netherlands : Imprint: Springer, 2008)