@article{MZ_1996__221_1_174837,
     author = {T.Y. Lam and A. Prestel and M.D. Choi},
     title = {Sums of 2m-th powers of rational functions in one variable over real closed fields.},
     journal = {Mathematische Zeitschrift},
     pages = {93--112},
     publisher = {mathdoc},
     volume = {221},
     number = {1},
     year = {1996},
     zbl = {0859.12002},
     url = {http://geodesic.mathdoc.fr/item/MZ_1996__221_1_174837/}
}