@incollection{AST_1980__75-76__47_0,
     author = {Brockett, R. W.},
     title = {Remarks on finite dimensional nonlinear estimation},
     booktitle = {Analyse des syst\`emes},
     series = {Ast\'erisque},
     pages = {47--55},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {75-76},
     year = {1980},
     zbl = {0458.93048},
     language = {en},
     url = {http://archive.numdam.org/item/AST_1980__75-76__47_0/}
}