【作者(必填)】Simon Freyaldenhoven   Christian Hansen   Jesse M. Shapiro

【文题(必填)】Pre-event Trends in the Panel Event-Study Design

【年份(必填)】2019

【全文链接或数据库名称(选填)】https://www.aeaweb.org/articles?id=10.1257/aer.20180609

求大神帮助！