@article{JRAM_1972__255_151240,
     author = {Paul S. Muhly},
     title = {A structure theory for isometric representations of a class of semigroups.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {135--154},
     publisher = {mathdoc},
     volume = {255},
     year = {1972},
     zbl = {0244.47030},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1972__255_151240/}
}