@article{SF_1983__26_134608,
     author = {T.A. Martynova},
     title = {The groupoid of 0-reduced varieties of {Semigroups} (n).},
     journal = {Semigroup forum},
     pages = {249--274},
     publisher = {mathdoc},
     volume = {26},
     year = {1983},
     zbl = {0546.20052},
     url = {http://geodesic.mathdoc.fr/item/SF_1983__26_134608/}
}