@article{SF_1980__20_134415,
     author = {A.J. Ovsyannikov},
     title = {Lattice isomorphisms of commutative relatively free semigroups.},
     journal = {Semigroup forum},
     pages = {189--226},
     publisher = {mathdoc},
     volume = {20},
     year = {1980},
     zbl = {0487.20037},
     url = {http://geodesic.mathdoc.fr/item/SF_1980__20_134415/}
}