The Development of Practice-based Research Networks in North America in Early Stage:a Literature Review from Historical Perspective 
WANG Yang, XU Zhijie, LI Li, KUANG Li, XU Yanli, HAN Jianjun
Chinese General Practice . 2021, (28): 3525 -3542 .  DOI: 10.12114/j.issn.1007-9572.2021.00.291