National Productivity Corporation. (2001). A glossary of productivity and quality terminologies. National Productivity Corporation.
Chicago-referens (17:e uppl.)National Productivity Corporation. A Glossary of Productivity and Quality Terminologies. Petaling Jaya: National Productivity Corporation, 2001.
MLA-referens (8:e uppl.)National Productivity Corporation. A Glossary of Productivity and Quality Terminologies. National Productivity Corporation, 2001.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.