@Article{406951,
     author = "Henryk Gurgul, Artur Machno, Robert Syrek",
     title = "The optimal portfolio in rescpect to Expected Shortfall: a comparative study",
     year =  2013,
     volume =  14,
     number =  ,
     journal =  Managerial Economics,
     pages =  s. 17-38,
    }