@article{SF_1976__12_134182,
     author = {T. Nordahl},
     title = {Bands of power-joined semigroups.},
     journal = {Semigroup forum},
     pages = {299--312},
     year = {1976},
     volume = {12},
     zbl = {0377.20048},
     url = {http://geodesic.mathdoc.fr/item/SF_1976__12_134182/}
}