@article{GDZPPN001254413, title = {Joint continuity of affine semigroup actions.}, journal = {Semigroup forum}, volume = {20}, year = {1980}, pages = {153-166}, zbl = {0447.22001}, url = {http://dml.mathdoc.fr/item/GDZPPN001254413} }
Helmer, D. Joint continuity of affine semigroup actions.. Semigroup forum, Tome 20 (1980) pp. 153-166. http://gdmltest.u-ga.fr/item/GDZPPN001254413/