@article{10_21136_CPM_1989_118392,
     author = {Kopperman, Ralph D. and Meyer, Paul R.},
     title = {Cardinal invariants of bitopological spaces},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {374--380},
     publisher = {mathdoc},
     volume = {114},
     number = {4},
     year = {1989},
     doi = {10.21136/CPM.1989.118392},
     mrnumber = {1027233},
     zbl = {0717.54016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1989.118392/}
}