1. Trefftz E (1926) Ein Gegenstueck zum Ritz’schen Verfahren. In: Proceedings of the 2nd international congress of applied mechanics, Zürich, pp 131–137
2. Kita E, Kamiya N (1995) Trefftz method: an overview. Adv Eng Software 24:3–12
3. Liu R-F, Yeih W, Kuo S-R, Chen Y-W (2006) Indirect T-Trefftz and F-Trefftz methods for solving boundary value problem of poisson equation. J Chinese Inst Eng 29(6):989–1006
4. Ciałkowski MJ, Frąckowiak A (2000) Heat functions and their applications to solving the heat conduction and mechanical problems. Wyd. Politechniki Poznańskiej, Poznań (in Polish)
5. Grysa K (2010) Trefftz functions and their application in solving inverse problems. Wyd. Politechniki Świętokrzyskiej, Kielce (in Polish)