@article{1093891206, author = {Schumm, George F.}, title = {${\rm S}3.02={\rm S}3.03$.}, journal = {Notre Dame J. Formal Logic}, volume = {15}, number = {1}, year = {1974}, pages = { 147-148}, language = {en}, url = {http://dml.mathdoc.fr/item/1093891206} }
Schumm, George F. ${\rm S}3.02={\rm S}3.03$.. Notre Dame J. Formal Logic, Tome 15 (1974) no. 1, pp. 147-148. http://gdmltest.u-ga.fr/item/1093891206/