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@article{IM_1984__76_143128, author = {C.N. Delzell}, title = {A continuous, constructive solution to {Hilbert's} 17th problem.}, journal = {Inventiones mathematicae}, pages = {365--384}, publisher = {mathdoc}, volume = {76}, year = {1984}, zbl = {0547.12017}, url = {http://geodesic.mathdoc.fr/item/IM_1984__76_143128/} }
C.N. Delzell. A continuous, constructive solution to Hilbert's 17th problem.. Inventiones mathematicae, Tome 76 (1984), pp. 365-384. http://geodesic.mathdoc.fr/item/IM_1984__76_143128/