%0 Journal Article %A Seminar, D. E. %T Some Elementary Converse Problems in Ordinary Differential Equations* %J Canadian mathematical bulletin %D 1968 %P 703-716 %V 11 %N 5 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-1968-084-0/ %R 10.4153/CMB-1968-084-0 %F 10_4153_CMB_1968_084_0