Miniakhmetov, R.M., and M.L. Tsymbler. 2012. “Integration of Fuzzy C-Means Clustering Algorithm With PostgreSQL Database Management System”. Numerical Methods and Programming (Vychislitel’nye Metody I Programmirovanie) 13 (32):46-52. https://en.num-meth.ru/index.php/journal/article/view/560.