%0 Journal Article %A Zhang, Dong %T An energy estimate of an exterior problem and a Liouville theorem for harmonic maps %J Annales de l'I.H.P. Analyse non linéaire %D 1994 %P 633-642 %V 11 %N 6 %I Gauthier-Villars %G en %F AIHPC_1994__11_6_633_0