%0 Journal Article %A Laffey, Thomas J. %T On a question of Hills concerning co-transposers %J Portugaliae mathematica %D 1985 %P 179-187 %V 43 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/PORMA_1985__43_1_114498/ %G en %F PORMA_1985__43_1_114498