@article{SF_1993__47_2_135280,
     author = {R. Goldstein and J. Teymouri},
     title = {Adjan's theorem and conjugacy in semigroups.},
     journal = {Semigroup forum},
     pages = {299--304},
     publisher = {mathdoc},
     volume = {47},
     number = {2},
     year = {1993},
     zbl = {0797.20043},
     url = {http://geodesic.mathdoc.fr/item/SF_1993__47_2_135280/}
}