@article{JMPA_1930_9_9__383_0,
     author = {Weatherburn, C. E.},
     title = {On the {Lines} of {Equidistance} of a {Family} of {Surfaces}},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {383--390},
     publisher = {Gauthier-Villars},
     volume = {Ser. 9, 9},
     year = {1930},
     language = {en},
     url = {http://www.numdam.org/item/JMPA_1930_9_9__383_0/}
}