Ninaroon, P., Sitthiwarongchai, C., Charoenboon, P. and Piyaekchai, K. 2022. Product quality upgrading to create added value of loyalty with wisdom products in Samut Songkhram Province, Thailand. International journal of health sciences. 6, S5 (Mar. 2022), 81–93. DOI:https://doi.org/10.53730/ijhs.v6nS5.5203.