National Productivity Board and National Productivity Association. (1982). Productivity digest (Singapore). Singapore: National Productivity Board and National Productivity Association.
শিকাগো স্টাইলে সাইটেশনNational Productivity Board and National Productivity Association. Productivity Digest (Singapore). Singapore: National Productivity Board and National Productivity Association, 1982.
এমএলএ সাইটেশনNational Productivity Board and National Productivity Association. Productivity Digest (Singapore). Singapore: National Productivity Board and National Productivity Association, 1982.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.