SAS/STAT 9.1 Users Guide, Volumes 1-7

Cressie, N.A.C. (1993), Statistics for Spatial Data , New York: John Wiley & Sons, Inc.

Duetsch, C.V. and Journel, A.G. (1992), GSLIB: Geostatistical Software Library and User's Guide , New York: Oxford University Press.

Hohn, M.E. (1988), Geostatistics and Petroleum Geology , New York: Van Nostrand Reinhold.