Source: https://www.amazon.com/Heal-Your-Headache-David-Buchholz/dp/0761125663/ref=as_li_ss_tl?ie=UTF8&qid=1452104204&sr=8-16&keywords=migraine&linkCode=sl1&tag=ahealthblog-20&linkId=d3fc9a031a22443083244dea9d9e4a40