@article{SF_1993__47_2_135289,
     author = {M.V. Lawson},
     title = {A note on a paper of {Joubert.}},
     journal = {Semigroup forum},
     pages = {389--392},
     publisher = {mathdoc},
     volume = {47},
     number = {2},
     year = {1993},
     url = {http://geodesic.mathdoc.fr/item/SF_1993__47_2_135289/}
}