7Van Dyne, L., & LePine extra-role behaviors J. A. (1998). Helping and voice Evidence and construct and predictive validity. Academy of Management Journal 41(1), 108-119.
8Van Dyne, L., Kamdar, D., & Joireman, J. (2008). In-role perceptions buffer the negative impact of low LMX on helping and enhance the positive impact of high LMX on voice. Journal of Applied Psychology, 93(6), 1195-1207.
9Whiting, S. W., Podsakoff, P. M., & Pierce, J. R. (2008). Effects of task performance, helping, voice, and organizational loyalty on performance appraisal ratings. Journal of Applied Psychology, 93(1), 125-139.
10Wood, S. J., & Wall, T. D. (2007). Work enrichment and employee voice in human resource management performance studies. International Journal of Human Resource Management, 18(7), 1335-1372.