@article{CM_1940__7__1_0, author = {Behrend, Felix}, title = {\"Uber Systeme reeller algebraischer Gleichungen}, journal = {Compositio Mathematica}, pages = {1--19}, publisher = {Johnson Reprint Corporation}, volume = {7}, year = {1940}, zbl = {0021.29301}, language = {de}, url = {www.numdam.org/item/CM_1940__7__1_0/} }
Behrend, Felix. Über Systeme reeller algebraischer Gleichungen. Compositio Mathematica, Tome 7 (1940) , pp. 1-19. http://www.numdam.org/item/CM_1940__7__1_0/