Popaitoon, S. “The Synergy of Intrinsic and Extrinsic Motivation on NPD Project Success : Case Study Approach of Technology-Intensive Firms”. Journal of HR Intelligence, vol. 14, no. 2, Oct. 2019, pp. 6-26, https://so03.tci-thaijo.org/index.php/hri/article/view/223595.