@article{02099340, title = {On upper and lower weakly }, journal = {Novi Sad Journal of Mathematics}, volume = {32}, year = {2002}, pages = {7-24}, zbl = {1050.54014}, language = {en}, url = {http://dml.mathdoc.fr/item/02099340} }
Popa, Valeriu; Noiri, Takashi. On upper and lower weakly . Novi Sad Journal of Mathematics, Tome 32 (2002) pp. 7-24. http://gdmltest.u-ga.fr/item/02099340/