@article{SF_1972__4_133878,
     author = {E.E. Devun},
     title = {The equivalence of uniquely divisible semigroups and uniquely representable semigroups on the two-cell.},
     journal = {Semigroup forum},
     pages = {69--72},
     publisher = {mathdoc},
     volume = {4},
     year = {1972},
     zbl = {0261.22002},
     url = {http://geodesic.mathdoc.fr/item/SF_1972__4_133878/}
}