United nations industrial development organization Vienna. (1973). The petrochemical industry. New York: United Nation.
Dyfyniad Arddull ChicagoUnited nations industrial development organization Vienna. The Petrochemical Industry. New York: United Nation, 1973.
Dyfyniad MLAUnited nations industrial development organization Vienna. The Petrochemical Industry. New York: United Nation, 1973.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.