@article{JRAM_1974__0268_0269_151471,
     author = {Emma Lehmer},
     title = {On the quartic character of quadratic units.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {294--301},
     publisher = {mathdoc},
     volume = {0268_0269},
     year = {1974},
     zbl = {0289.12007},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1974__0268_0269_151471/}
}