@article{CLTM_2004_2004_1_a16,
     author = {Szepietowski, Blazek},
     title = {Involuciones en grupos de clases de aplicaciones de superficies no orientables.},
     journal = {Collectanea mathematica},
     pages = {253-260},
     publisher = {mathdoc},
     volume = {55},
     number = {3},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CLTM_2004_2004_1_a16/}
}