Controlled study of efficacy and safety of two oral doses of zolpidem ( 10 and 20 mg). In: Sauvanet JP, Lager SZ, Morselli PL, eds. Imidazopyridines in sleep disorders: a novel experimental and therapeutic approach. - Lorizio,A.; Terzano,M.; Parrino,L. (LERS Monograph series. New York: Raven Press, 1988)