@article{10_1017_S0017089500004687,
     author = {Munn, W. D.},
     title = {An embedding theorem for free inverse semigroups},
     journal = {Glasgow mathematical journal},
     pages = {217--222},
     year = {1981},
     volume = {22},
     number = {2},
     doi = {10.1017/S0017089500004687},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500004687/}
}