Review
Combination analgesia in 2005 - a rational approach: focus on paracetamol-tramadol.
Clin. Rheumatol. 2006 Jan 1;25 Suppl 1:S16-21.
Meta Analysis
Single-patient data meta-analysis of 3453 postoperative patients: oral tramadol versus placebo, codeine and combination analgesics.
Pain. 1997 Feb 1; 69 (3): 287294287-294.
Randomized Controlled Trial
Combining diclofenac with acetaminophen or acetaminophen-codeine after oral surgery: a randomized, double-blind single-dose study.
Clin. Pharmacol. Ther. 1999 Dec 1;66(6):625-35.