Wongsaphan, Montree, et al. “Evaluation of a Contextual Problem-Based Learning (CoPBL) Model Integrated With Ethno-SSI Using a School Herbal Garden to Strengthen Students’ 21st-Century Skills and Sustainable Living”. Journal of Engineering Education Transformations, vol. 40, no. 1, Oct. 2026, pp. 159-68, doi:10.16920/jeet/2026/v40is1/26160.