A double-blind, randomized and placebo-controlled study on the polysomnographic withdrawal effects of zopiclone, zolpidem and triazolam in healthy subjects. - Voderholzer, U.; Riemann, D.; Hornyak, M.; Backhaus, J.; Feige, B.; Berger, M.; Hohagen, F. (European Archives of Psychiatry & Clinical Neuroscience, 2001)