@article{SF_1980__21_134454,
     author = {Simon M. Goberstein},
     title = {Fundamental order relations on inverse semigroups and on their generalizations.},
     journal = {Semigroup forum},
     pages = {285--328},
     publisher = {mathdoc},
     volume = {21},
     year = {1980},
     zbl = {0456.20044},
     url = {http://geodesic.mathdoc.fr/item/SF_1980__21_134454/}
}