@incollection{AST_1984__118__13_0,
     author = {Almgren, F. J. and Super, B.},
     title = {Multiple valued functions in the geometric calculus of variations},
     booktitle = {Variational methods for equilibrum problems of fluids - Trento, 20-25 juin 1983},
     series = {Ast\'erisque},
     pages = {13--32},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {118},
     year = {1984},
     zbl = {0575.49025},
     language = {en},
     url = {http://archive.numdam.org/item/AST_1984__118__13_0/}
}