@article{10_1017_S0017089500009861,
     author = {Cowan, David and Reilly, Norman R.},
     title = {Characterizations of {Sch\"utzenberger} graphs in terms of their automorphism groups and fundamental groups},
     journal = {Glasgow mathematical journal},
     pages = {275--291},
     year = {1993},
     volume = {35},
     number = {3},
     doi = {10.1017/S0017089500009861},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500009861/}
}