@article{GDZPPN00244481X,
title = {Sums of 2m-th powers of rational functions in one variable over real closed fields.},
journal = {Mathematische Zeitschrift},
volume = {221},
year = {1996},
pages = {93-112},
zbl = {0859.12002},
url = {http://dml.mathdoc.fr/item/GDZPPN00244481X}
}
Lam, T.Y.; Prestel, A.; Choi, M.D. Sums of 2m-th powers of rational functions in one variable over real closed fields.. Mathematische Zeitschrift, Tome 221 (1996) pp. 93-112. http://gdmltest.u-ga.fr/item/GDZPPN00244481X/