Risma Hesti Yuni Astuti, et al. “Upaya Meningkatkan Kepercayaan Diri Siswa Kelas IX H Melalui Bimbingan Klasikal Model Problem Based Learning Di SMP Negeri 1 Semarang”. Educatio, vol. 19, no. 1, June 2024, pp. 200-9, doi:10.29408/edc.v19i1.25807.