1. American Concrete Institute Committee 340 “Design Handbook in Accordance with Strength Design Method of ACI 318–71 ” Vol. 1 ACI Special Publication SP‐17(73) American Concrete Institute Detroit Mich. 1973 432 pp.
2. Gouwens A. J. “Biaxial Bending Simplified ” Reinforced Concrete Columns (SP‐50) Detroit: American Concrete Institute 1975 pp. 233–261.