@article{JRAM_1971__247_151094,
     author = {Pierre Antoine Grillet and M.P. Grillet},
     title = {On strict extensions of semigroups.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {75--79},
     publisher = {mathdoc},
     volume = {247},
     year = {1971},
     zbl = {0234.20031},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1971__247_151094/}
}