2RA Harvey and Shirley E Morris, Pathways to productivity improvement[J].Omega,volume9,1ssue2,1981,143-153.
3Alicia Kritsonis, Asse:ssing A Firm' s Future Financial Health[J]. International Journal of Scholarey Academic lnterlectual Diversity,volume 9,Number 1 2004-2005.
4Manuel L, Jose, Carol Lancaster, Jerry L. Stevens. Corporate Returns and Cash Conversion Cycles[J]. Journal of Economics and Finance, 1996,Spring:33-46.