1. Frequency of spontaneous tumours in NMRI mice in 21-month studies;Bomhard;Exp. Toxicol. Pathol.,1993
2. Spontaneous tumours in NMRI mice from carcinogenicity studies;Bomhard;Exp. Pathol.,1989
3. Metabolism of tramadol in man and animals;Erlaçin;Naunyn-Schmiedeberg's Arch. Pharmacol.,1980
4. Influence of tramadol on neurotransmitter systems of the rat brain;Frink;Arzneim.-Forsch./Drug Res.,1996
5. Tumour incidence and tumour spectrum of male Han:NMRI mice;Kaspareit;Z. Versuchstierkd.,1987