@Article{406950,
     author = "Henryk Gurgul, Roland Mestel, Robert Syrek",
     title = "The Testing of Casual Stock Returns-Trading Volume Dependencies with the Aid of Copulas",
     year =  2013,
     volume =  13,
     number =  ,
     journal =  Managerial Economics,
     pages =  s. 21-44,
    }