University of Chicago. Industrial Relations Center. (1967). Exchange: Elementary school economics III (Field test ed.). Industrial Relations Center, University of Chicago.
Dyfyniad Arddull ChicagoUniversity of Chicago. Industrial Relations Center. Exchange: Elementary School Economics III. Field test ed. Chicago: Industrial Relations Center, University of Chicago, 1967.
Dyfyniad MLAUniversity of Chicago. Industrial Relations Center. Exchange: Elementary School Economics III. Field test ed. Industrial Relations Center, University of Chicago, 1967.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.