National Productivity Council. (1963). Report no.28 glass industry in Britan and U.S.A. N.P.C.
Dyfyniad Arddull ChicagoNational Productivity Council. Report No.28 Glass Industry in Britan and U.S.A. N.P.C, 1963.
Dyfyniad MLANational Productivity Council. Report No.28 Glass Industry in Britan and U.S.A. N.P.C, 1963.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.