@article{1183741688, author = {Urquhart, Alasdair}, title = {The Undecidability of Entailment and Relevant Implication}, journal = {J. Symbolic Logic}, volume = {49}, number = {1}, year = {1984}, pages = { 1059-1073}, language = {en}, url = {http://dml.mathdoc.fr/item/1183741688} }
Urquhart, Alasdair. The Undecidability of Entailment and Relevant Implication. J. Symbolic Logic, Tome 49 (1984) no. 1, pp. 1059-1073. http://gdmltest.u-ga.fr/item/1183741688/