@article{GDZPPN002191350,
title = {Periodic expansions and units in quadratic and cubic number fields.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {272},
year = {1975},
pages = {266-277},
zbl = {0321.12011},
url = {http://dml.mathdoc.fr/item/GDZPPN002191350}
}
Denenberg, Charlotte Goryn. Periodic expansions and units in quadratic and cubic number fields.. Journal für die reine und angewandte Mathematik, Tome 272 (1975) pp. 266-277. http://gdmltest.u-ga.fr/item/GDZPPN002191350/