@article{00845472, title = {Complexity of the decidability of one class of formulas in quantifier-free set theory with a set-union operator.}, journal = {Georgian Mathematical Journal}, volume = {3}, year = {1996}, pages = {97-100}, doi = {10.1007/BF02256801}, zbl = {0852.03016}, language = {en}, url = {http://dml.mathdoc.fr/item/00845472} }
Tetruashvili, M. Complexity of the decidability of one class of formulas in quantifier-free set theory with a set-union operator.. Georgian Mathematical Journal, Tome 3 (1996) pp. 97-100. doi : 10.1007/BF02256801. http://gdmltest.u-ga.fr/item/00845472/