Central European Journal of Mathematics
Central European Journal of Mathematics > 2006 > 4 > 2 > 260-269
Central European Journal of Mathematics > 2008 > 6 > 4 > 568-575
Central European Journal of Mathematics > 2011 > 9 > 3 > 686-698
Central European Journal of Mathematics > 2011 > 9 > 6 > 1435-1447
Central European Journal of Mathematics > 2013 > 11 > 8 > 1375-1391