@article{SF_1977__15_134231,
     author = {H. J\"urgensen},
     title = {Computers in semigroups.},
     journal = {Semigroup forum},
     pages = {1--20},
     publisher = {mathdoc},
     volume = {15},
     year = {1977},
     zbl = {0372.20002},
     url = {http://geodesic.mathdoc.fr/item/SF_1977__15_134231/}
}