@article{JRAM_1992__431_153453,
     author = {Gian Pietro Pirola},
     title = {On a conjecture of {Xiao.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {75--90},
     publisher = {mathdoc},
     volume = {431},
     year = {1992},
     zbl = {0753.14040},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1992__431_153453/}
}