BuldyginV. V., and DemyanenkoO. O. “On Asymptotic Properties of the Empirical Correlation Matrix of a Homogeneous Vector-Valued Gaussian Field”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 52, no. 3, Mar. 2000, pp. 300-18, https://umj.imath.kiev.ua/index.php/umj/article/view/4420.