@article{SF_1981__23_134511,
     author = {D. Helmer},
     title = {Continuity of semigroup actions.},
     journal = {Semigroup forum},
     pages = {153--189},
     publisher = {mathdoc},
     volume = {23},
     year = {1981},
     zbl = {0473.22002},
     url = {http://geodesic.mathdoc.fr/item/SF_1981__23_134511/}
}