1. Trefftz E. Ein Gegenstuck zum Ritzschen Verfharen. In: Proc 2nd Int Cong Appl Mech. Zurich, 1926:131–137.
2. Herrera I. Trefftz Method. In: Brebbia CA, editor. Topics in boundary element research, vol. 1: basic principles and applications, Chap. 10. New York: Springer-Verlag, 1984:225–253.
3. Quinlan PM. The edge function method in elastostatistics. In: studies in numerical analysis. London: Academic Press, 1974.
4. Direct solution procedure for solution of harmonic problems using complete, non-singular, Trefftz functions;Cheung;Com Appl Num Meth,1989
5. Generalized finite element analysis with T-complete boundary solution functions;Zielinski;Int J Num Meth Engng,1985