Vikent’ev, A.A., and M.S. Avilov. 2016. “New Comprehensive Metrics and Nontrivial Steps to Formulas Multi-Valued Logic in the Automatic Clustering of Logical Formulas Knowledge Base. II”. Bulletin of the Karaganda University. Mathematics Series 83 (3):46-54. https://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/102.