@article{NAM_1912_4_12__337_0,
     author = {Haag, J.},
     title = {Sur la d\'eformation infiniment petite des surfaces r\'egl\'ees},
     journal = {Nouvelles annales de math\'ematiques : journal des candidats aux \'ecoles polytechnique et normale},
     pages = {337--358},
     publisher = {Carilian-Goeury et Vor Dalmont},
     volume = {4e s{\'e}rie, 12},
     year = {1912},
     language = {fr},
     url = {http://www.numdam.org/item/NAM_1912_4_12__337_0/}
}