%0 Journal Article
%A Jaak Peetre
%T The Euler derivative. An intrinsic approach to the calculus of variations.
%J Mathematica Scandinavica
%D 1978
%P 313-333
%V 42
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MS2_1978__42_166595/
%F MS2_1978__42_166595