@article{MAN_1910__68_158445,
     author = {G. Sannia},
     title = {Geometria differenziale delle congruenze rettilinee},
     journal = {Mathematische Annalen},
     pages = {409--416},
     year = {1910},
     volume = {68},
     zbl = {41.0733.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1910__68_158445/}
}