@phdthesis{BJHTUP11_1990__0276__P0_0,
     author = {Robbiano, Luc},
     title = {Unicit\'e du probl\`eme de {Cauchy} : ensembles nodaux : r\'egularit\'e des probl\`emes elliptiques},
     series = {Th\`eses d'Orsay},
     publisher = {Universit\'e de Paris-Sud Centre d'Orsay},
     number = {276},
     year = {1990},
     language = {fr},
     url = {http://www.numdam.org/item/BJHTUP11_1990__0276__P0_0/}
}