@article{NAM_1920_4_20__55_1,
     author = {Th\'ebault, V.},
     title = {Sur les contacts des sph\`eres tangentes \`a quatre plans},
     journal = {Nouvelles annales de math\'ematiques : journal des candidats aux \'ecoles polytechnique et normale},
     pages = {55--59},
     publisher = {Carilian-Goeury et Vor Dalmont},
     volume = {4e s{\'e}rie, 20},
     year = {1920},
     language = {fr},
     url = {http://www.numdam.org/item/NAM_1920_4_20__55_1/}
}