@article{1077378481, author = {Malitz, Jerome}, title = {Universal classes in infinitary languages}, journal = {Duke Math. J.}, volume = {36}, number = {1}, year = {1969}, pages = { 621-630}, language = {en}, url = {http://dml.mathdoc.fr/item/1077378481} }
Malitz, Jerome. Universal classes in infinitary languages. Duke Math. J., Tome 36 (1969) no. 1, pp. 621-630. http://gdmltest.u-ga.fr/item/1077378481/