@article{1183502141, author = {Stopher, E. C.}, title = {Point set operators and their interrelations}, journal = {Bull. Amer. Math. Soc.}, volume = {45}, number = {11}, year = {1939}, pages = { 758-762}, language = {en}, url = {http://dml.mathdoc.fr/item/1183502141} }
Stopher, E. C. Point set operators and their interrelations. Bull. Amer. Math. Soc., Tome 45 (1939) no. 11, pp. 758-762. http://gdmltest.u-ga.fr/item/1183502141/