@article{PORMA_1962__21_3_114889,
     author = {Carvalho, J.B. de and Tamari, Dov},
     title = {Sur l'associativit\'e partielle des sym\'etrisations de semi-groupes},
     journal = {Portugaliae mathematica},
     pages = {157--169},
     publisher = {mathdoc},
     volume = {21},
     number = {3},
     year = {1962},
     mrnumber = {0150215},
     zbl = {0113.25101},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1962__21_3_114889/}
}