1. Aizicovici, S., Fečkan, M.: Forced symmetric oscillations of evolution equations. Nonlinear Anal. 64, 1621–1640 (2006)
2. Berger, M.S.: Nonlinearity and Functional Analysis. Academic Press, New York (1977)
3. Berman, G.P., Izrailev, F.M.: The Fermi–Pasta–Ulam problem: fifty years of progress. Chaos 15, 015104 (2005)
4. Berman, G.P., Kolovskii, A.R.: Stochasticity limit of a one-dimensional chain of interacting oscillators. Sov. Phys. JETP 60, 1116 (1984)
5. Birkhoff, G., Mac Lane, S.: A Survey of Modern Algebra. A K Peters Ltd., Natick (2008)