Hong Zhu 0003 Hongbo Li Zongmin Cui Zhongsheng Cao Meiyi Xie EFTG: Efficient and Flexible Top-K Geo-textual Publish/Subscribe. 5877-5897 2018 12 KSII Trans. Internet Inf. Syst. 12 https://doi.org/10.3837/tiis.2018.12.015 db/journals/itiis/itiis12.html#ZhuLCCX18