Tech Clusters2020-08-0144 OA AI WWilliam R. Kerr *FFrédéric Robert‐Nicoud DOI:10.1257/jep.34.3.50原文链接原文求助分享收藏摘要 En Keyword:KNOWLEDGE SPILLOVERS PRODUCTION NETWORKS PATENT CITATIONS SILICON VALLEY INNOVATION MOBILITY ENTREPRENEURSHIP LOCALIZATION GEOGRAPHY LOCATION