@article{JMPA_1857_2_2__110_0,
     author = {Liouville, J.},
     title = {Sur l'expression $\varphi\left(n\right)$, qui marque combien la suite $1,2,3,\ldots,n$ contient de nombres premiers \`a $n$},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {110--112},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 2},
     year = {1857},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1857_2_2__110_0/}
}