Fedorov, V.V. (1989). Kriging and other estimators of spatial field characteristics (with special reference to environmental studies). Atmospheric Environment (1967) 23 (1), 175-184. 10.1016/0004-6981(89)90110-8.
Fedorov, V.V. (1989). Optimal design with bounded density: optimization algorithms of the exchange type. Journal of Statistical Planning and Inference 22 (1), 1-13. 10.1016/0378-3758(89)90060-8.