Hair, Jr., J.F., Anderson, R.E., Tatham, R.L., and Black, W.C.(1998) : Multivariate data analysis, Prentice-hall Internatinal, Inc., p.190-191.
Mitchell, A.R. and van Genuchten, M. Th.(1993): Flood irrigation of cracked soil, Soil Sci. Soc. Am. J., 57 : 490-497.
Pillai, U.P. and McGarry, D.(1999): Structure repair of a compacted vertisol with wet-dry cycles and crops, Soil Sci. Soc. Am. J., 63 : 201-210.
Utomo, W.H. and Dexter, A.R.(1981):Soil Friability, J. Soil Sci., 32 : 203-213.
Waldron, L. J. and Dakessian, S.(1981):Soil reinforcement by roots : calculation of increased soil shear resistance from root properties, Soil Sci.,132 : 427-435.