@article{SF_1976__12_134162,
     author = {Ju.G. Koselev},
     title = {Varieties preserved under wreath products.},
     journal = {Semigroup forum},
     pages = {95--108},
     year = {1976},
     volume = {12},
     zbl = {0338.20095},
     url = {http://geodesic.mathdoc.fr/item/SF_1976__12_134162/}
}