Kriging, in the scientific literature, is used as a name for the theory of prediction in random processes (random fields) with an unknown mean value and, possibly, with an unknown covariance function. M. Stein in a series of articles (1988), (1990a), (1990b) and (1990c) studies the case when the unknown covariance function of the observed process is misspecified, but not estimated from the data...