@article{GDZPPN002418282, title = {Characterization of Fans and Hereditarily Pythagorean Fields.}, journal = {Mathematische Zeitschrift}, volume = {147}, year = {1976}, pages = {149-164}, zbl = {0319.12102}, url = {http://dml.mathdoc.fr/item/GDZPPN002418282} }
Bröcker, Ludwig. Characterization of Fans and Hereditarily Pythagorean Fields.. Mathematische Zeitschrift, Tome 147 (1976) pp. 149-164. http://gdmltest.u-ga.fr/item/GDZPPN002418282/