1. Sahs AL, Nibbelink OW, Torner JC, eds.Aneurysmal Subarachnoid Hemorrhage. Report of the Cooperative Study.Baltimore: Urban & Schwarzenberg, 1981
2. Bisplinghoff RL, Mar JW, Pian THH.Statics of Deformable Solids,New York: Dover Publications, Inc., 1965