1. V.V.Novozhilov, ?Thin Shell Theory? 2nd edition, (P. Noordhoff Ltd., 1964).
2. I.N.Vekua, ?New Methods of Solving Elliptic Equations?, (North Holland Publ.Co., 1961).
3. D.A.Newton, ?A Contribution to the Analysis of Boundary Value Problems in Thin Shells?, Thesis submitted for Ph.D., Univ. of Southampton, 1967.
4. L.Fox, ?Numerical Solution of Two Point Boundary Value Problems?, O.U.P.
5. F.A.Leckie, D.J.Payne, and R.R.K.Penny ?Elliptical Discontinuities in Spherical Shells?, J. of Strain Analysis, Jan., 1967.