@article{PORMA_1974__33_2_115220,
     author = {Donnell, William},
     title = {A note on entropic groupoids},
     journal = {Portugaliae mathematica},
     pages = {77--78},
     publisher = {mathdoc},
     volume = {33},
     number = {2},
     year = {1974},
     mrnumber = {0333032},
     zbl = {0287.20053},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1974__33_2_115220/}
}