%0 Journal Article %A Ronald A. Knight %T Certain closed flows on a 2-manifold %J Annales Polonici Mathematici %D 1981 %P 95-104 %V 40 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/ap-40-1-95-104/ %R 10.4064/ap-40-1-95-104 %G en %F 10_4064_ap_40_1_95_104