@article{10_14708_cm_v29i2_6276,
     author = {T. Kreid},
     title = {Combinatorial operators},
     journal = {Commentationes Mathematicae},
     pages = { 243--249},
     publisher = {mathdoc},
     volume = {29},
     number = {2},
     year = {1990},
     doi = {10.14708/cm.v29i2.6276},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/cm.v29i2.6276/}
}