@article{MAN_1980__251_163437,
     author = {Jacek Bochnak and Gustave Efroymson},
     title = {Real {Algebraic} {Geometry} and the 17th {Hilbert} {Problem.}},
     journal = {Mathematische Annalen},
     pages = {213--242},
     publisher = {mathdoc},
     volume = {251},
     year = {1980},
     zbl = {0425.14004},
     url = {http://geodesic.mathdoc.fr/item/MAN_1980__251_163437/}
}