1. Nadai, A.: Theory of Flow and Fracture of Solid, Vol. 1, 2nd ed., p. 472. New York: McGraw-Hill. 1950.
2. Drucker, D. C.: A More Fundamental Approach to Plastic Stress-Strain Relations. Proc. U.S. Nat'l. Congr. Appl. Mech.487 (1951).
3. Budiansky, B.: Extension of Michell's Theorem to Problem of Plasticity and Creep. Quart. Appl. Math.16, 307 (1958).
4. Budiansky, B.: A Reassessment of Deformation Theories of Plasticity. J. Appl. Mech.26, 259 (1959).
5. Mendelson, A.: Plasticity: Theory and Application, p. 119. New York: The McMillan Company. 1968.