@incollection{AST_1980__75-76__57_0,
     author = {Byrnes, Christopher I.},
     title = {On certain problems of arithmetic arising in the realization of linear systems with symmetries},
     booktitle = {Analyse des syst\`emes},
     series = {Ast\'erisque},
     pages = {57--65},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {75-76},
     year = {1980},
     mrnumber = {581702},
     zbl = {0458.93015},
     language = {en},
     url = {http://archive.numdam.org/item/AST_1980__75-76__57_0/}
}