@article{AIHPC_2003__20_3_405_0,
     author = {Burton, G. R. and Douglas, R. J.},
     title = {Uniqueness of the polar factorisation and projection of a vector-valued mapping},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {405--418},
     publisher = {Elsevier},
     volume = {20},
     number = {3},
     year = {2003},
     doi = {10.1016/S0294-1449(02)00026-4},
     mrnumber = {1972869},
     zbl = {1038.28013},
     language = {en},
     url = {http://archive.numdam.org/articles/10.1016/S0294-1449(02)00026-4/}
}