National Productivity Board and National Productivity Association. (1982). Productivity digest (Singapore). Singapore: National Productivity Board and National Productivity Association.
Dyfyniad Arddull ChicagoNational Productivity Board and National Productivity Association. Productivity Digest (Singapore). Singapore: National Productivity Board and National Productivity Association, 1982.
Dyfyniad MLANational Productivity Board and National Productivity Association. Productivity Digest (Singapore). Singapore: National Productivity Board and National Productivity Association, 1982.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.