Thuần, H., Thạnh, L.M. and Tuấn, T.C. 2012. Analysis of some methods to avoid infinite loops in the process of query valuation for the datalog proograms. Journal of Computer Science and Cybernetics. 18, 2 (Jul. 2012), 119–127. DOI:https://doi.org/10.15625/1813-9663/18/2/1597.