@article{SF_1992__44_1_135125,
     author = {J. Leech},
     title = {Normal skew lattices.},
     journal = {Semigroup forum},
     pages = {1--8},
     year = {1992},
     volume = {44},
     number = {1},
     zbl = {0754.06004},
     url = {http://geodesic.mathdoc.fr/item/SF_1992__44_1_135125/}
}