@article{CMH_1990__65_3_140196,
     author = {Fernando Serrano},
     title = {Multiple fibres of a morphism.},
     journal = {Commentarii mathematici Helvetici},
     pages = {287--298},
     publisher = {mathdoc},
     volume = {65},
     number = {3},
     year = {1990},
     zbl = {0714.14008},
     url = {http://geodesic.mathdoc.fr/item/CMH_1990__65_3_140196/}
}