1. Benton, W C Jr. (2007) Purchasing and Supply Management, McGraw-Hill/Irwin, New York, USA.
2. Leenders, M R, Johnson, P F, Flynn, A E and Fearon, H E (2006) Purchasing and Supply Management: With 50 Supply Chain Cases, 13th edition, McGraw-Hill/Irwin, USA.
3. Lysons, K and Farrington, B (2006) Purchasing and Supply Chain Management, Pearson Education Limited, England.
4. The Sun, Thursday April 23, 2009 p. 1, member of audit bureau of circulations (Malaysia) www.sun2surf.com
5. Wisner, J D, Leong, G K and Tan, K C (2005) Principles of Supply Chain Management: A Balanced Approach, South-Western, Thomson, USA.