PB - University of Technology L1 - http://smp.pm.szczecin.pl/Content/1572/PMRes_2011_1.pdf L2 - http://smp.pm.szczecin.pl/Content/1572 ER - T1 - Polish Maritime Research. No 1 (68) 2011 UR - http://smp.pm.szczecin.pl/dlibra/docmetadata?id=1572