9Daniel T C, Sharpley A N, Lemunyon J L. Agricultural phosphorus and eutrophication: a symposium overview. Journal of Environmental Quality, 1998, 27:251-257.
10Hooda P S, Rendell A R, Edwords A C, Withers P J A, Aitken M N,Truesdals V W. Relating soil phosphorus indices to potential phosphorus release to water. Journal of Environmental Quality, 2000,29:1 166-1 171.