1. 5 activities outside the classroom that students should do to increase their chances of getting a job. Retrieved on January 10, 2018 from https://www.jobthai.com/REACH/career-tips/5-กิจกรรมนอกห้องเรียนที่นักศึกษาควรทำเพื่อเพิ่มโอกาสในการได้งาน.html
2. Chickering, A.W. (1969). Education and Identity. San Francisco: Jossey-Bass.
3. Chickering, A. W., & L. Reisser, L. (1993). Education and identity (2nd ed.). San Francisco: Jossey-Bass.
4. Dowling, P. (1998). The Sociology of Mathematics Education: Mathematical Myths/ Pedagogic Texts. London: The Falmer Press.
5. Hammerman, R.D., Hammerman,M.W. & Hammerman,L.E. (1994). Teaching in the outdoor. America: Clnterstate.
6. Monpilai Norasing. (2017). People development for driving Thailand to Thailand 4.0. MGR Online. Retrieved on January 10, 2018 from https://mgronline.com/daily/detail/ 9600000120293.
7. Panisa Meejinda. (2010). Consumer Behavior. Bangkok: Dhamma-sarn.
8. Research Administration and Quality Assurance Division. (2017). Thailand 4.0 Blueprint for Driving Thailand to Prosperity, Stability and Sustainability.
9. Sasaklak Thongpandee. (2008). The Study of Self-Development Needs of Employees of Power Pump Company (Master’s Thesis). Ramkhamhaeng University, Graduate School, Human Resource Development Major, Bangkok.
10. Smith, P. G. (1976). Knowledge and Values. Education Theory. 26, 29-39.
11. Suwimol, Manjing. (2009). Marketing Management. Bangkok: Se-Education.
12. Winai Phetchchuay. Self-Development. Retrieved on January 10, 2018