@article{MAN_1974__207_162533,
     author = {Gilbert Stengle},
     title = {A {Nullstellensatz} and a {Positivstellensatz} in {Semialgebraic} {Geometry.}},
     journal = {Mathematische Annalen},
     pages = {87--98},
     publisher = {mathdoc},
     volume = {207},
     year = {1974},
     zbl = {0253.14001},
     url = {http://geodesic.mathdoc.fr/item/MAN_1974__207_162533/}
}