1. Soil mechanics and plastic analysis of limit design;Drucker;Q. appl. Math.,1952
2. Mixed boundary value problems in soil mechanics;Shield;Q. appl. Math.,1953
3. Stress and velocity fields in soil mechanics;Shield;J. Math. Phys.,1955
4. Axially symmetric plastic deformations in soils;Cox;Phil. Trans. R. Soc.,1961
5. The Mathematical Theory of Plasticity;Hill,1950