Disparity analysis of patient portal messaging use for COVID-19 in urban versus rural locality. - Ming Huang 006; Andrew Wen; Huan He; Liwei Wang 010; Sijia Liu 002; Yanshan Wang; Nansu Zong; Yue Yu; Julie E. Prigge; Brian Costello; Nilay D. Shah; Henry Ting; et al. (AMIA, 2021)