Ford, J. Kevin; Schmitt, Neal; Schechtman, Susan L.; Hults, Brian M.; Doherty, Mary L. (1989). "Process Tracing Methods: Contributions, Problems, and Neglected Research Questions". Organizational Behavior and Human Decision Processes. 43 (1): 75–117. doi:10.1016/0749-5978(89)90059-9.