Lộc, V.M. 2012. An expression for measyring the degree of the truth of inclusion with interval-valued fuzzy sets and application to resoning based on fuzzy sets. Journal of Computer Science and Cybernetics. 18, 2 (Jul. 2012), 141–149. DOI:https://doi.org/10.15625/1813-9663/18/2/1600.