@article{CMUC_1990__31_2_a22,
     author = {Sun, Shu Hao and Choo, Koo Guan},
     title = {Some new cardinal inequalities involving a cardinal function less than the spread and the density},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {395--401},
     publisher = {mathdoc},
     volume = {31},
     number = {2},
     year = {1990},
     mrnumber = {1077911},
     zbl = {0717.54002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1990__31_2_a22/}
}