Finley, Andrew O., Abhirup Datta, and Sudipto Banerjee. “SpNNGP R Package for Nearest Neighbor Gaussian Process Models”. Journal of Statistical Software 103, no. 5 (July 11, 2022): 1–40. Accessed August 15, 2022. https://www.jstatsoft.org/index.php/jss/article/view/v103i05.