1. Kačianauskas, R. 1995.Computer Methods in Multilevel Modelling of Beams and Shells395Vilnius: Technika.
2. Crisfield, M. A. 1991.Non-linear Finite Element Analysis of Solids and Structures, 1, Essentials.350Chichester: John Wiley & Sons.
3. Bathe, K-J. 1982.Finite Element Procedures in Engineering Analysis, New-Jersey: Prentice-Hall406
4. Zienkewicz, O. C. 1977.The Finite Element Method, 3d ed.787New-York: McGraw-Hill.