1. Richart, F., Brandtzæg, A., and Brown, R. (1928). A Study of the Failure of Concrete under Combined Compressive Stresses, University of Illinois at Urbana Champaign.
2. Hognestad, E. (1951). Study of Combined Bending and Axial Load in Reinforced Concrete, University of Illinois at Urbana Champaign.
3. Sargin, M. (1971). Stress-Strain Relationships for Concrete and the Analysis of Structural Concrete Sections, Solid Mechanics Division, University of Waterloo.
4. A Numerical Approach to the Complete Stress-Strain Curve of Concrete;Popovics;Cem. Concr. Res.,1973
5. Stress-Strain Curves of Normal and Lightweight Concrete in Compression;Wang;ACI J.,1978