@article{SF_1970__1_133783,
     author = {J.D. Lawson and B. Madison},
     title = {Peripherality in semigroups.},
     journal = {Semigroup forum},
     pages = {128--142},
     publisher = {mathdoc},
     volume = {1},
     year = {1970},
     zbl = {0206.30602},
     url = {http://geodesic.mathdoc.fr/item/SF_1970__1_133783/}
}