@article{GRSME_2004_2004_1_a13,
     author = {Powers, Victoria},
     title = {Sumas de cuadrados, polinomios positivos y optimizaci\'on en conjuntos semialgebraicos.},
     journal = {La Gaceta de la Real Sociedad Matem\'atica Espa\~nola},
     pages = {539-552},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {2004},
     language = {es},
     url = {http://geodesic.mathdoc.fr/item/GRSME_2004_2004_1_a13/}
}