Ispurwanto, W. ., Murti, T. R. ., Yunanto, K. T. ., Abraham, J. ., Nainggolan, T. . and Nugroho, R. . (2021) “A Performance Model of the Indonesian National Police: The Role of Communication Apprehension, Servant Leadership, Group Cohesiveness, and Silence Behavior”, Humanities and Social Sciences Letters, 9(4), pp. 326–340. doi: 10.18488/journal.73.2021.94.326.340.