@article{DMSMF_2005_2005_1_a2,
     author = {Ying, Daniel},
     title = {On trigonal {Riemann} surfaces with non-unique morphims},
     journal = {Disertaciones del Seminario de Matem\'aticas Fundamentales},
     pages = {1-11},
     year = {2005},
     volume = {34},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMSMF_2005_2005_1_a2/}
}