Variational problems on classes of rearrangements and multiple configurations for steady vortices G. R. Burton — 1989 Annales de l'I.H.P. Analyse non linéaire
Uniqueness of the polar factorisation and projection of a vector-valued mapping G. R. Burton; R. J. Douglas — 2003 Annales de l'I.H.P. Analyse non linéaire