@article{SF_1983__27_134633,
     author = {A.N. Trahtman},
     title = {The finite basis question for semigroups of order less than six.},
     journal = {Semigroup forum},
     pages = {387--389},
     publisher = {mathdoc},
     volume = {27},
     year = {1983},
     url = {http://geodesic.mathdoc.fr/item/SF_1983__27_134633/}
}