@article{SF_1983__26_134611,
     author = {R.J. Koch},
     title = {Comparison of congruences on regular semigroups.},
     journal = {Semigroup forum},
     pages = {295--306},
     publisher = {mathdoc},
     volume = {26},
     year = {1983},
     zbl = {0508.20033},
     url = {http://geodesic.mathdoc.fr/item/SF_1983__26_134611/}
}