@article{CMUC_1973_14_2_a2,
     author = {Simon, Petr},
     title = {A note on cardinal invariants of square},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {205--213},
     year = {1973},
     volume = {14},
     number = {2},
     mrnumber = {0339044},
     zbl = {0258.54003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1973_14_2_a2/}
}