P. Thongpool, S. Peanprasit, P. Wirotecheewan, N. Chindaprasert, K. Lertlaokul, and P. Tinprabath, “STUDY ON DRYING OF KRATOM LEAVES USING FLUIDIZED BED METHOD”, PSRU J. Sci. Tech., vol. 10, no. 3, pp. 122–139, Dec. 2025.