@article{1183736622, author = {Materna, Pavel}, title = {Identity, Equivalence and Isomorphism of Problems}, journal = {J. Symbolic Logic}, volume = {34}, number = {1}, year = {1969}, pages = { 24-34}, language = {en}, url = {http://dml.mathdoc.fr/item/1183736622} }
Materna, Pavel. Identity, Equivalence and Isomorphism of Problems. J. Symbolic Logic, Tome 34 (1969) no. 1, pp. 24-34. http://gdmltest.u-ga.fr/item/1183736622/