%0 Journal Article %A Kenneth Leland %T Characterizations of solutions of Δf=cf %J Studia Mathematica %D 1967 %P 125-132 %V 29 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/sm-29-2-125-132/ %R 10.4064/sm-29-2-125-132 %G en %F 10_4064_sm_29_2_125_132