Minghua Jiang Shuqing Ma Ming Hu Yixiang Ding Availability Analytical Model for Web Services of an E-learning Development Platform. 972-975 2008 CSSE (5) http://dx.doi.org/10.1109/CSSE.2008.207 conf/csse/2008-5 db/conf/csse/csse2008-5.html#JiangMHD08