National Productivity Board and National Productivity Association. (1986). Productivity digest (Singapore). Singapore: National Productivity Board and National Productivity Association.
Trích dẫn kiểu ChicagoNational Productivity Board and National Productivity Association. Productivity Digest (Singapore). Singapore: National Productivity Board and National Productivity Association, 1986.
Trích dẫn MLANational Productivity Board and National Productivity Association. Productivity Digest (Singapore). Singapore: National Productivity Board and National Productivity Association, 1986.
Cảnh báo: Các trích dẫn này có thể không phải lúc nào cũng chính xác 100%.