@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/