RIES AL. (1990). BOTTOM UP MARKETING. PLUME BOOK.
Dyfyniad Arddull ChicagoRIES AL. BOTTOM UP MARKETING. NEW YORK: PLUME BOOK, 1990.
Dyfyniad MLARIES AL. BOTTOM UP MARKETING. PLUME BOOK, 1990.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.