@article{10_21136_CMJ_1966_100741,
     author = {Hasse, Maria and Michler, Lothar},
     title = {Einige {Bemerkungen} \"uber freie {Kategorien} und freie {Gruppoide}},
     journal = {Czechoslovak Mathematical Journal},
     pages = {424--445},
     publisher = {mathdoc},
     volume = {16},
     number = {3},
     year = {1966},
     doi = {10.21136/CMJ.1966.100741},
     mrnumber = {0197375},
     zbl = {0224.18001},
     language = {ge},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1966.100741/}
}