Sphenoid SinusitisNEJM 309:1149-1154, Lew,D.,et al, 1983
Headache in Cerebrovascular DiseaseIn Handbk Clx Neurol, Ed, Vinken & Bruyn, Elsevier Publ Co, Ch 11, V 5, p. 124, Fisher,C.M., 1975