Kumar, P and Joshi, P K and Johansen, C and Asokan, M (2000) Total factor productivity of rice-wheat cropping systems in India - the role of legumes. In: Legumes in rice and wheat cropping systems of the Indo-Gangetic Plain - constraints and opportunities. International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India, pp. 166-175. ISBN 92-9066-418-5