@Article{91564,
     author = "Lidia Mierzejewska, Jerzy J. Parysek",
     title = "Regional differences in the age structure of Poland's population in the years 1999-2010 : a multivariate approach ",
     year =  2013,
     volume =  ,
     number =  19,
     journal =  Bulletin of Geography. Socio-Economic Series,
     pages =  s. 61-72,
    }