Do primary healthcare facilities in more remote areas provide more medical services? Spatial evidence from rural western China / Chi Shen, Sha Lai, Qiwei Deng, Dan Cao, Dantong Zhao, Yaxin Zhao, Zhongliang Zhou (Xian Jiaotong University), Wanyue Dong (Nanjing University of Chinese Medicine), Xi Chen (Yale University and IZA) ; IZA - Institute of Labor Economics