Budiastra, I.W. and Jannah, F.R. 2022. Non Destructive Determination of Soursop Firmness and Sweetness With Ultrasonic Method. Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering). 11, 2 (Jun. 2022), 253–265. DOI:https://doi.org/10.23960/jtep-l.v11i2.253-265.