%0 Journal Article %A Jung, Hyung Chan %A Lee, Jeh Gwon %T On the jump number of lexicographic sums of ordered sets %J Czechoslovak Mathematical Journal %D 2003 %P 343-349 %V 53 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMJ_2003__53_2_a9/ %G en %F CMJ_2003__53_2_a9