Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Susan Athey and Stefan Wager,Policy Learning With Observational Data,Econometrica,0012-9682,The Econometric Society,2021,89,1,133-161,https://cir.nii.ac.jp/crid/1360861293077664256,https://doi.org/10.3982/ecta15732