@article{JMPA_1923_9_2__99_0,
     author = {Vessiot, E.},
     title = {Contribution \`a la g\'eom\'etrie conforme. {Cercles} et surfaces cercl\'ees},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {99--165},
     publisher = {Gauthier-Villars},
     volume = {9e s{\'e}rie, 2},
     year = {1923},
     language = {fr},
     url = {http://archive.numdam.org/item/JMPA_1923_9_2__99_0/}
}