7Ghods M, Nelson K M. Contributors to quality during software maintenance [ J ]. Decision Support Systems, 1998,23 (4) : 361 -369.
8Pfleeger S L, Atlee J M. Software engineering:theory and prac- tice [ M ]. New Jersey : Prentice-Hall, Ine ,2006.
9Sneed H M, Anecon G H, Vienna A. A cost model for software maintenance & evolution[ C ]//Proe of 20th IEEE internation- al conference on software maintenance. [ s. 1. ] : IEEE, 2004 : 264 -273.
10Muthanna S, Knotogiannis K, Ponnambalam K, et al. A main- tainability model for industrial software systems using design level metrics[ C]//Proc of 7th working conference on reverse engineering. Brisbane : IEEE ,2000:248-256.
