@article{CSHM_1991_2_1__41_0,
     author = {Becker, Eberhard},
     title = {Sums of squares and quadratric forms in real algebraic geometry},
     journal = {Cahiers du s\'eminaire d'histoire des math\'ematiques},
     pages = {41--57},
     publisher = {Institut Henri Poincar\'e, S\'eminaire d'histoire des math\'ematiques : Paris},
     volume = {Ser. 2, 1},
     year = {1991},
     mrnumber = {1122204},
     zbl = {0746.14021},
     language = {en},
     url = {http://archive.numdam.org/item/CSHM_1991_2_1__41_0/}
}