@article{10_4064_cm_55_2_377_385,
     author = {V. V. Tkachuk},
     title = {On a cardinal invariant resembling the {Souslin} number},
     journal = {Colloquium Mathematicum},
     pages = {377--385},
     publisher = {mathdoc},
     volume = {55},
     number = {2},
     year = {1987},
     doi = {10.4064/cm-55-2-377-385},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-55-2-377-385/}
}