Ratnawulan, Ratnawulan. 2022. “Increasing The Competence of Science Teachers in The Batusangkar City through Technical Guidance on 21st Century Learning Implementation in Integrated Science Student Worksheet”. Pelita Eksakta 5 (1), 28-36. https://doi.org/10.24036/pelitaeksakta/vol5-iss1/169.