1. H. G. Allen, Analysis and Design of Structural Sandwich Panels. Pergamon Press, Oxford (1969)
2. H. G. Allen and P. S. Bulson, Background to Buckling. McGraw-Hill (1980)
3. W. C. Young, Roark's Formulas for Stress and Strain. McGraw-Hill, New York (1989)
4. H. Wagner, Remarks on Airplane Struts and Girders under Compression and Bending Stresses; Index Values. National Advisory Committee for Aeronautics, NACA TM 50, Washington, USA (1929a)