1. Maluf J.W., Faria F.F., Ulhoa S.C.: Class. Quantum Grav. 24, 2743–2753 (2007) [arXiv:0704.0986]
2. Lanczos C.: The Variational Principles of Mechanics. Dover, New York (1986)
3. Goldstein H.: Classical Mechanics. Addison-Wesley, Reading (1980)
4. Brown J.D., York J.W. Jr: Phys. Rev. D 40, 3312 (1989)
5. Maluf J.W., da Rocha-Neto J.F., Toríbio T.M.L.: Castello-Branco, K.H.: Phys. Rev. D 65, 124001 (2002) [gr-qc/0204035]