Abano, E.E., Sam-Amoah, L.K. and Bart-Plange, A. 2013. Variation in ultrasonic frequency and time as pre-treatments to air-drying of carrot. Journal of Agricultural Engineering. 43, 4 (Mar. 2013), e23. DOI:https://doi.org/10.4081/jae.2012.e23.