1. Ahmad, Badu & Batinggi. 2013. Public Service Management. Andi Publisher: Yogyakarta.
2. Language Development and Cultivation Agency. 2016. Big Indonesian Dictionary. Jakarta: Balai Pustaka.
3. Creswell, John W. 2015. Qualitative Research & Research Design: Choosing among Five Approaches. (3rd ed.). Student Library: Yogyakarta.
4. Danim, Sudarwan. 2012. Leadership Motivation and Group Effectiveness. Jakarta: Rineka Cipta.
5. Dwiyanto, Agus. 2014. Realizing Good Governance Through Public Services. Yogyakarta: Gadjah Mada, University Press.