พึงวัฒนานุกูล ผศ.อรุณี. 2019. “Marketing Mix Strategy in Buying Decision Making of the Royal Project’s Organic Vegetables of the Elderly in Bangkok”. Pathumthani University Academic Journal 11 (1):278-82. https://so05.tci-thaijo.org/index.php/ptujournal/article/view/188460.