@article{SF_1991__42_3_135069,
     author = {B. Piochi},
     title = {Solvability and the permutation property in inverse semigroups.},
     journal = {Semigroup forum},
     pages = {113--116},
     year = {1991},
     volume = {42},
     number = {3},
     zbl = {0729.20031},
     url = {http://geodesic.mathdoc.fr/item/SF_1991__42_3_135069/}
}