%0 Journal Article %A Zelinka, Bohdan %T On a problem of R. Halin concerning subgraphs of infinite graphs %J Mathematica slovaca %D 1977 %P 43-45 %V 27 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/MASLO_1977__27_1_a5/ %G en %F MASLO_1977__27_1_a5