Vikent’ev, A.A. “Study of Model Distances on Logical Statements Based on Expert Interpretation of the Formulas of Many-Valued Logics of Lukasiewicz and Automatic Clustering of Knowledge Bases. I”. Bulletin of the Karaganda University. Mathematics Series, vol. 82, no. 2, June 2016, pp. 23-31, http://mts.buketov.edu.kz/index.php/mathematics-vestnik/article/view/87.