@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/}
}