@article{10_4064_fm179_2_2,
     author = {Ljubi\v{s}a D. R. Ko\v{c}inac and Marion Scheepers},
     title = {Combinatorics of open covers {(VII):} {Groupability}},
     journal = {Fundamenta Mathematicae},
     pages = {131--155},
     publisher = {mathdoc},
     volume = {179},
     number = {2},
     year = {2003},
     doi = {10.4064/fm179-2-2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm179-2-2/}
}