@article{PORMA_1967__26_4_115046,
     author = {Morgado, Jos\'e},
     title = {A theorem on entropic groupoids},
     journal = {Portugaliae mathematica},
     pages = {449--452},
     publisher = {mathdoc},
     volume = {26},
     number = {4},
     year = {1967},
     mrnumber = {0255715},
     zbl = {0208.29601},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1967__26_4_115046/}
}