Wu, Yahui, Mingxing Liu, Su Deng, Hongbin Huang, and Yiqi Deng. 2015. “Optimal Caching Policy of Stochastic Updating Information in Delay Tolerant Networks”. Computing and Informatics 33 (5):965-91. http://147.213.75.17/ojs/index.php/cai/article/view/866.