Yurekli VA, Akhan G, Kutluhan S, Uzar E, Koyuncuoglu HR, Gultekin F (2008). "The effect of sodium valproate on chronic daily headache and its subgroups". J Headache Pain(en inglés)9 (1): 37–41. PMID18231713. doi:10.1007/s10194-008-0002-5.
Davis MA, Kononowech RW, Rolin SA, Spierings EL (2008). "Acupuncture for Tension-Type Headache: A Meta-Analysis of Randomized, Controlled Trials". J Pain(en inglés). PMID18499526. doi:10.1016/j.jpain.2008.03.011.
Yurekli VA, Akhan G, Kutluhan S, Uzar E, Koyuncuoglu HR, Gultekin F (2008). "The effect of sodium valproate on chronic daily headache and its subgroups". J Headache Pain(en inglés)9 (1): 37–41. PMID18231713. doi:10.1007/s10194-008-0002-5.
Davis MA, Kononowech RW, Rolin SA, Spierings EL (2008). "Acupuncture for Tension-Type Headache: A Meta-Analysis of Randomized, Controlled Trials". J Pain(en inglés). PMID18499526. doi:10.1016/j.jpain.2008.03.011.