61Naqvzp+ML._UF1000,1000_QL80_.jpg。PDF] A Gentle Introduction to Stata, Revised Sixth Edition Free。41TrSn9n23L._UF350,350_QL50_.jpg。Amazon.com: A Gentle Introduction to Stata, Revised Sixth。。A gentle introduction to STATASixth editionAlan C. Acock, Oregon Stare UniversityStata pressISBN 9781597182690