Hong Wan Peng Guo Zhengdong Wang Tianjie Zhao Chunhong Meng Gang Yang Research on Droutht Monitoring in Shandong Provience Based on Multi-Source Remote Sensing Data. 9428-9430 2019 IGARSS https://doi.org/10.1109/IGARSS.2019.8897998 conf/igarss/2019 db/conf/igarss/igarss2019.html#WanGWZMY19