@article{SF_1975__10_134115,
     author = {C.F. Dunkl},
     title = {Bounded derivations on commutative semigroups.},
     journal = {Semigroup forum},
     pages = {229--237},
     year = {1975},
     volume = {10},
     zbl = {0298.43003},
     url = {http://geodesic.mathdoc.fr/item/SF_1975__10_134115/}
}