@article{GDZPPN002195828,
title = {Orderings under field extensions.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {310},
year = {1979},
pages = {7-27},
zbl = {0398.12019},
url = {http://dml.mathdoc.fr/item/GDZPPN002195828}
}
Lam, T.Y.; Elman, R.; Wadsworth, A.R. Orderings under field extensions.. Journal für die reine und angewandte Mathematik, Tome 310 (1979) pp. 7-27. http://gdmltest.u-ga.fr/item/GDZPPN002195828/