Gisin V., Volkova E. (2018). Representation of tolerance relations valued in complete heyting algebras and granulation of fuzzy information. System analysis in economics – 2018: Proceedings of the V International research and practice conference–biennale (21–23 november 2018). Moscow, Prometheus publishing house, pp. 189-191. DOI: 10.33278/SAE-2018.eng.189-191