Lithuanian Mathematical Journal
Lithuanian Mathematical Journal > 2015 > 55 > 2 > 270-290
Lithuanian Mathematical Journal > 2015 > 55 > 4 > 543-554
Lithuanian Mathematical Journal > 2015 > 55 > 4 > 489-505
Lithuanian Mathematical Journal > 2015 > 55 > 2 > 270-290
Lithuanian Mathematical Journal > 2015 > 55 > 4 > 543-554
Lithuanian Mathematical Journal > 2015 > 55 > 4 > 489-505