Lesauskienė, Edita, and Kęstutis Dučinskas. “Estimation of Covariance Functions for Spatio-Temporal Data”. Lietuvos matematikos rinkinys 43, no. spec. (December 22, 2003): 515–519. Accessed November 6, 2025. https://www.zurnalai.vu.lt/LMR/article/view/32520.