@article{RSMUP_1961__31__232_0,
     author = {Lions, Jacques Louis},
     title = {On a trace problem},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {232--242},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {31},
     year = {1961},
     mrnumber = {158287},
     zbl = {0102.10702},
     language = {en},
     url = {http://www.numdam.org/item/RSMUP_1961__31__232_0/}
}