1. Agterberg, F. P., 1970, Autocorrelation functions in geology, Geostatistics, Ed. D. F. Merriam, Plenum Press, pp. 113–141.
2. Andrews, D. F., Bickel, P. J., Hampel, F. R., Hubel,P. J., Rogers, W. H., Tukey, J. W., 1972, Robust Estimates of Location, Princeton Univ. Press, 371 p.
3. Cressie, N and Hawkins, D. M., 1980, Robust estimation of the variogram: I, Math. Geology, V. 12, N. 2, pp. 115–125.
4. Draper, N. R. and Smith, H., 1968, Applied Regression Analysis, Wiley, 407 pp.
5. Huijbregts, Ch., 1971, Reconstitution du variogramme ponctuel a partir d’un variogramme experimental regularize, Ecole de Mines de Paris, 26 pp.