@article{GDZPPN00219001X,
title = {Pure quartic number fields whose class numbers are even.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {272},
year = {1975},
pages = {102-112},
zbl = {0312.12006},
url = {http://dml.mathdoc.fr/item/GDZPPN00219001X}
}
Parry, Charles J. Pure quartic number fields whose class numbers are even.. Journal für die reine und angewandte Mathematik, Tome 272 (1975) pp. 102-112. http://gdmltest.u-ga.fr/item/GDZPPN00219001X/