@article{SF_1996__52_3_135433,
     author = {J.D. Lawson},
     title = {The earliest semigroup paper?},
     journal = {Semigroup forum},
     pages = {55--60},
     year = {1996},
     volume = {52},
     number = {3},
     zbl = {0844.22001},
     url = {http://geodesic.mathdoc.fr/item/SF_1996__52_3_135433/}
}