@article{SF_1980__19_134391,
     author = {A. Varisco and Spoletini A. Cherubini},
     title = {Quasi commutative semigroups and a-reflective semigroups.},
     journal = {Semigroup forum},
     pages = {313--322},
     publisher = {mathdoc},
     volume = {19},
     year = {1980},
     zbl = {0432.20053},
     url = {http://geodesic.mathdoc.fr/item/SF_1980__19_134391/}
}