The first author is grateful to FAPESP, CNPQ, and the Russian Foundation for Basic Research (grant no. 13-01-00239). The second author is grateful to SNI, Mexico. The third author is grateful to the Russian Foundation for Basic Research (grant no. 2014/319, project no. 258). The fourth author is grateful for support to his work given by 2012-2013 FAPESP Grant processo 2012/11068-2 and 2012-2013 CONACYT Grant for the Sabbatical Year at the Institute of Mathematics and Statistics of the University of Sao Paulo, Sao Paulo, Brazil.