1. Barchard, K. A., & Pace, L. A., (2010). Poka-Yoke Data Entry System Version 1.18. Excel file that shows how to set up a double-entry data entry system for any number of measures and items. .
2. Meeting the challenge of high quality data entry: A free double-entry system;Barchard;International Journal of Services and Standards,2008
3. The PowerChecker: A Visual Basic program for ensuring data integrity;Beaty;Behavior, Research Methods, Innovation, & Computers,1999
4. Outliers and improper solutions;Bollen;Sociological Methods & Research,1987
5. Data management: Recommended practices;Burchinal;Monographs of the Society for Research in Child Development,2006