1. Andersen G. (1979). “Brugervejledning for FEMOPT. Program for optimenng af baerende konstruktioner.” (“Users' manual for FEMOPT. Program for the optimizing of load‐carrying structures ” in Danish.) Note no. 7902 Inst. Bldg. Tech. Struct. Engrg. Aalborg Univ. Centre Aalborg Denmark.
2. Cedervall K. and Fransson L. (1979). “The effect of reinforcement on the carrying capacity of an ice cover.” Publ. 79:1 Avd. för Konstrukttionsteknik Høgskolan i Luleå Sweden.
3. Gerard G. (1962). Introduction to structural stability theory . 1st ed. McGraw‐Hill New York N.Y. 89–94.