9Yildirm V.Governing equations of initially twisted elastic space rods made of laminated composite materials[J].International Journal of Engineering Sciences,1999,37(8): 1007-1035.
10Yildirm V,Sancaktar E.Linear free vibration analysis of cross-ply laminated cylindrical helical springs[J].International Journal of Mechanical Sciences,2000,42(6): 1153-1169.