References
- Schriften v.2 The beginning of research in the calculus of variations Caratheodory,C.
- Methods of Mathematical Physics v.1;2 Courant,R.;D.Hilbert
- Calculus of Variations Gelfand,I.M.;S.V.Fomin
- Calculus of Variations Giaquina,M.;S.Hildebrandt
- A History of the Calculus of Variations from the 17th through the 19th Century Goldstine,H.
- The Parsimorious Universe Hildebrandt,S.;A.Tromba
- Critical Point Theory and Hamiltonian Systems Mawhin,J.;M.Willem
- Stories about Maxima and Minima Tikhomirov,V.M.