@article{SF_1982__24_134553,
     author = {I.O. Korjakov},
     title = {A sketch of the lattice of commutative nilpotent semigroup varieties.},
     journal = {Semigroup forum},
     pages = {285--318},
     publisher = {mathdoc},
     volume = {24},
     year = {1982},
     zbl = {0493.20039},
     url = {http://geodesic.mathdoc.fr/item/SF_1982__24_134553/}
}