Nurtanto, Muhammad, Soffan Nurhaji, Jamil Abd Baser, and Yadin Yadin. 2018. “Problem-Based Learning Implementation: Improvement in Learning Process and Results in Vocational Higher Education”. Jurnal Pendidikan Teknologi Dan Kejuruan 24 (2):203-12. https://doi.org/10.21831/jptk.v24i2.19519.