1. Drug therapy for preventing post-dural puncture headache;Basurto Ona;Cochrane Database of Systematic Reviews,2009
2. Caffeine revisited;Beaver;JAMA,1984
3. The number needed to treat: a clinically useful measure of treatment effect;Cook;BMJ,1995
4. Single-dose analgesic studies: the upside and downside of assay sensitivity. The Design of Analgesic Clinical Trials;Cooper;Advances in Pain Research Therapy,1991
5. A primer on caffeine pharmacology and its drug interactions in clinical psychopharmacology;Donovan;Psychopharmacol Bulletin,2001