%0 Journal Article %A T. Flett %T Some applications of Zygmund's lemma to nonlinear differential equations in Banach and Hilbert spaces %J Studia Mathematica %D 1972 %P 335-344 %V 44 %N 4 %U http://geodesic.mathdoc.fr/articles/10.4064/sm-44-4-335-344/ %R 10.4064/sm-44-4-335-344 %G en %F 10_4064_sm_44_4_335_344