Buldygin, V.V., et al. “On the Papers of M.I. Yadrenko on the Theory of Random Fields ”. Ukrains’kyi Matematychnyi Zhurnal, vol. 44, no. 11, Nov. 1992, pp. 1460-5, https://umj.imath.kiev.ua/index.php/umj/article/view/8246.