Wibowo, Wicaksono Ari, et al. “Development of a Digital-Based Sit and Reach Box for Measuring Body Flexibility”. Jurnal Maenpo : Jurnal Pendidikan Jasmani Kesehatan Dan Rekreasi, vol. 13, no. 1, June 2023, pp. 100-1, doi:10.35194/jm.v13i1.3272.