@article{BSMA_1877_2_1_1_337_1,
     author = {Borchardt, C.-W.},
     title = {Sur la moyenne arithm\'etique-g\'eom\'etrique de quatre \'el\'ements},
     journal = {Bulletin des Sciences Math\'ematiques et Astronomiques},
     pages = {337--348},
     publisher = {Gauthier-Villars},
     volume = {2e s{\'e}rie, 1},
     number = {1},
     year = {1877},
     language = {fr},
     url = {http://www.numdam.org/item/BSMA_1877_2_1_1_337_1/}
}