@article{SF_1972__5_133940,
     author = {Y. Zalcstein},
     title = {Locally testable semigroups.},
     journal = {Semigroup forum},
     pages = {216--227},
     publisher = {mathdoc},
     volume = {5},
     year = {1972},
     zbl = {0273.20049},
     url = {http://geodesic.mathdoc.fr/item/SF_1972__5_133940/}
}