@article{NAM_1861_1_20__284_1,
     author = {Prinz, A.},
     title = {Question 572, d\'emonstration de la formule $L.2=4 \Big (\frac{1}{1.2.3}+\frac{1}{5.6.7}+\frac{1}{9.10.11}+\cdots \Big )$},
     journal = {Nouvelles annales de math\'ematiques : journal des candidats aux \'ecoles polytechnique et normale},
     pages = {284--286},
     publisher = {Carilian-Goeury et Vor Dalmont},
     volume = {1e s{\'e}rie, 20},
     year = {1861},
     language = {fr},
     url = {http://www.numdam.org/item/NAM_1861_1_20__284_1/}
}