1. Black, C.A., 1965. Methods of Soil Analysis. Part 2. Chemical and Microbiological Properties. American Society of Agronomy, Madison, WI.
2. Bronson, K.F., Cassman, K.G., Wassmann, R., Olk, D.C., van Noordwijk, M., Garrity, D.P., 1997. Soil carbon dynamics in different cropping systems in principal ecoregions of Asia. In: Lal, R., Kimble, J., Follett, R.F., Stewart, B.A. (Eds.), Management of Carbon Sequestration in Soil. CRC Press, Boca Raton, New York, pp. 35–57.
3. Sequential phosphorus extraction of a 33P-labeled oxisol under contrasting agricultural systems;Buehler;Soil Sci. Soc. Am. J.,2002
4. Fractionation of soil phosphorus;Chang;Soil Sci.,1957
5. How widespread are yield declines in long-term rice experiments in Asia?;Dawe;Field Crops Res.,2000