1. Olhoff, N. and Rasmussen, S.H., “On Single and Bimodal Optimum Buckling Loads of Clamped Columns,” Int. J. Solids and Structures, Vol. 13, 1977, pp. 605–614.
2. Masur, E.F. and Mroz, Z., “Singular Solutions in Structural Optimization Problems,” Proceedings, IUTAM Symposium On Variational Methods In The Mechanics Of Solids, (Ed. ST Nemat- Nasser), Pergamon Press, New York, to appear 1980.
3. Prager, S. and Prager, W., “A Note on Optimal Design of Columns,” Int. J. Mech. Sci., Vol. 21, 1979, pp. 249–251.
4. Haug, E.J. and Rousselet, B., “Design Sensitivity Analysis in Structural Mechanics I: Static Response Variations,” J. Str. Mech., Vol. 8, No. 1, 1980, pp. 17–41.
5. Haug, E.J. and Rousselet, B., “Design Sensitivity Analysis in Structural Mechanics II: Eigenvalue Variations,” J. Str. Mech., Vol. 8, No. 2, 1980.