Croassacipto, M., M. Ichwan, and D. B. Utami. “Tone Classification Matches Kodàly Handsign With the K-Nearest Neighbor Method at Leap Motion Controller”. International Journal on Information and Communication Technology (IJoICT), Vol. 5, no. 2, June 2020, pp. 40-45, doi:10.21108/IJOICT.2019.52.283.