@article{GDZPPN002197804,
title = {Signatures of units and congruences (mod 4) in certain totally real fields.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {316},
year = {1980},
pages = {1-5},
zbl = {0439.12003},
url = {http://dml.mathdoc.fr/item/GDZPPN002197804}
}
Lagarias, J.C. Signatures of units and congruences (mod 4) in certain totally real fields.. Journal für die reine und angewandte Mathematik, Tome 316 (1980) pp. 1-5. http://gdmltest.u-ga.fr/item/GDZPPN002197804/