@article{GDZPPN002233118, title = {The intersection theorem for orderings of higher level in rings.}, journal = {Manuscripta mathematica}, volume = {76}, year = {1992}, pages = {273-278}, zbl = {0758.12003}, url = {http://dml.mathdoc.fr/item/GDZPPN002233118} }
Berr, Ralph. The intersection theorem for orderings of higher level in rings.. Manuscripta mathematica, Tome 76 (1992) pp. 273-278. http://gdmltest.u-ga.fr/item/GDZPPN002233118/