@article{SF_1976__13_134229,
     author = {C. Maxson and M. Zeller},
     title = {Elementary ...-languages and finite semilattices of groups.},
     journal = {Semigroup forum},
     pages = {385--386},
     publisher = {mathdoc},
     volume = {13},
     year = {1976},
     zbl = {0359.20065},
     url = {http://geodesic.mathdoc.fr/item/SF_1976__13_134229/}
}