@article{NAM_1871_2_10__26_1,
     author = {Lemonnier, H.},
     title = {D\'emonstration des expressions de $\cos (a \pm b), \sin (a \pm b)$},
     journal = {Nouvelles annales de math\'ematiques : journal des candidats aux \'ecoles polytechnique et normale},
     pages = {26--28},
     publisher = {Carilian-Goeury et Vor Dalmont},
     volume = {2e s{\'e}rie, 10},
     year = {1871},
     language = {fr},
     url = {http://www.numdam.org/item/NAM_1871_2_10__26_1/}
}