3Heizer J, Render B. Operations management [M]. 7th Edition. New Jersey : Pearson Education Inc., 2003 : 122.
4Meyers F E, Stephens M P. Manufacturing facilities design and material handling [ M ]. 2nd Edition. New Jersey: Prentice Hall Inc., 2000:76.
5Goldman S L, Nagel R N, Preiss K. Agile competitors and virtual organizations: strategies for enrich the customer [ M]. New York; Van Nostrand Reinhold, 1995:82.