1. V.I. Arnold. Mathematical methods of classical mechanics. Springer-Verlag, Berlin, 1989.
2. V.I. Arnold, V.V. Kozlov, and A.I. Neistadt. Mathematical aspects of classical and celestial mechanics, volume 3 of Encycl. of Math. Sciences. Springer, 1988.
3. H.H. Goldstine. A history of the calculus of variations from the 17th through the 19th century. Springer-Verlag, Berlin, 1980.
4. F. Klein. Vorlesungen uber die Entwicklung der Mathematik. Verlag von Julius Springer, Berlin, 1927.
5. C. Lanczos. The variational principles of mechanics. University of Toronto Press, Toronto, 1962.