@article{10_4064_cm_57_2_221_227,
     author = {Mario Gionfriddo},
     title = {Partial parallel classes in {Steiner} systems},
     journal = {Colloquium Mathematicum},
     pages = {221--227},
     publisher = {mathdoc},
     volume = {57},
     number = {2},
     year = {1989},
     doi = {10.4064/cm-57-2-221-227},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-57-2-221-227/}
}