@Article{429041,
     author = "Michael Hanias, Lykourgos Magafas, P. Konstantaki",
     title = "Non Linear Analysis of S&P Index",
     year =  2013,
     volume =  8,
     number =  4,
     journal =  Equilibrium. Quarterly Journal of Economics and Economic Policy,
     pages =  s. 125-135,
    }