1. Intravenous tramadol for post-operative pain—comparison of intermittent dose regimens with and without maintenance infusion;Chrubasik;Eur J Anaesthesiol,1992
2. Tramadol;Eggers;Br J Anaesthesia,1995
3. Tramadol revisited;Budd;Br J Anaesth,1999
4. The hypoalgesic effect of tramadol in relation to CYP2D6;Poulsen;Clin Pharmacol Ther,1996
5. Tramadol in musculoskeletal pain—a survey;Reig;Clin Rheumatol,2002