1. Occipital Headaches
The emergency physician can be reassured that organic causes of headache occur rarely { Between 4.5% to 20% of headache patients visiting the ED will be suffering from vascular headaches. This type of headache is usually easy to differentiate...
http://www.usdoctor.com/sym2.htm

2. New Hope for Headache Sufferers
Whether they are mild or severe, brief or enduring, right- or left-sided, frontal or occipital, headaches are, at best, an annoyance, and, at worst, a sign of life threatening pathology. I first became aware of this source of headaches when I...
http://www.webspawner.com/users/newhopeforheadaches/

3. MedlinePlus: Headache
(American Headache Society, Committee on Headache Education) Headaches: The most common type of headache is a tension headache. Headaches can have many causes, but serious causes of headaches are rare.
http://www.nlm.nih.gov/medlineplus/headache.html