1. W.T. Koiter, On the stability of elastic equilibrium, Thesis, Delft, 1945, (English transl. NASA TT-F10, 883, 1967 and AFFDL⧹TR70-25, 1970).
2. Higher order approximations in the calculation of elastic buckling loads of imperfect systems;Ho;Int. J. Non-Linear Mech.,1971
3. The influence of imperfections on systems with coincident buckling loads;Ho;Int. J. Non-linear Mech.,1972
4. Buckling load of non-linear systems with multiple eigenvalues;Ho;Int. J. Solids Struct.,1974
5. W.T. Koiter, Some properties of (completely) symmetric multilinear forms with an application to Ho's theorem for multi-mode buckling, Laboratory Report No. 587, Technologic University of Delft, The Netherlands, April 1976.