Ferinia, R. ., T. . Yuniarsi, and H. Disman. “Contribution of Employee Engagement and Interpersonal Relationship to Improve Employee Performance”. International Journal of Management and Sustainability, vol. 5, no. 7, Oct. 2016, pp. 48-60, doi:10.18488/journal.11/2016.5.7/11.7.48.60.