@article{GDZPPN002190400,
title = {Real closures of commutative rings. I.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {272},
year = {1975},
pages = {61-89},
zbl = {0331.13007},
url = {http://dml.mathdoc.fr/item/GDZPPN002190400}
}
Knebusch, Manfred. Real closures of commutative rings. I.. Journal für die reine und angewandte Mathematik, Tome 272 (1975) pp. 61-89. http://gdmltest.u-ga.fr/item/GDZPPN002190400/