Nunkaew, A. .; Makchuchit, N. .; Boonrat, A. . Development of a Learning Activity Package Based on Carl R. Roger’s Instructional Model for Enhancing Professional Competencies in Safety and Mechanic Tool Use of the 1st Year Vocational Certificate Students, Songkhla Polytechnic College. pnujrhuso 2022, 9, 112-129.