@article{AIHPA_1966__5_3_217_0,
     author = {Boillat, Guy},
     title = {Vitesses des ondes \'electrodynamiques et lagrangiens exceptionnels},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {217--225},
     publisher = {Gauthier-Villars},
     volume = {5},
     number = {3},
     year = {1966},
     language = {fr},
     url = {http://www.numdam.org/item/AIHPA_1966__5_3_217_0/}
}