1. Injected Morphine in Postoperative Pain
Henry J McQuay, Dm, Dawn Carroll, BA, Hons, R.Andrew Moore, DSc 
Journal of Pain and Symptom Management 
Volume 17, Issue 3, Pages (March 1999)
DOI: /S (98)

2. Fig. 1
Relation between the proportion of patients achieving at least 50% pain relief with 10 mg intramuscular morphine and with placebo in 15 trials
Journal of Pain and Symptom Management  , DOI: ( /S (98) )

3. Fig. 2
Funnel plot of relative benefit against total number of patients in the morphine/placebo comparison
Journal of Pain and Symptom Management  , DOI: ( /S (98) )

4. Fig. 3
Relative efficacy of single doses of analgesics compared with placebo to produce at least 50% pain relief in moderate or severe postoperative pain (oral doses except for morphine). Data for drugs other than morphine are from other published systematic reviews,8,9 and for ibuprofen see Reference 7
Journal of Pain and Symptom Management  , DOI: ( /S (98) )