อิงคามระธร ท. “THE UPGRADING TO SMART FARMER BY LEARNING FROM MASTER SMART FARMER OF PINEAPPLE PLANTATION FARMER IN RATCHABURI PROVINCE”. Phranakhon Rajabhat Research Journal : Humanities and Social Sciences, vol. 14, no. 2, Oct. 2018, pp. 121-34, https://so05.tci-thaijo.org/index.php/PNRU_JHSS/article/view/131834.