Dučinskas, Kęstutis, and Edita Lesauskienė. “Separable Spatio-Temporal Covariance Functions”. Lietuvos matematikos rinkinys 42, no. spec. (December 20, 2002): 497–500. Accessed February 26, 2026. https://www.journals.vu.lt/LMR/article/view/32983.