@article{SF_1980__20_134429,
     author = {S. Rankin and J. Johnson},
     title = {Semigroups and lattices.},
     journal = {Semigroup forum},
     pages = {385--386},
     publisher = {mathdoc},
     volume = {20},
     year = {1980},
     zbl = {0449.20068},
     url = {http://geodesic.mathdoc.fr/item/SF_1980__20_134429/}
}