Sahak, M. S. “Demographic Influences and 21st Century Skills by Trainee Teachers for Mathematics Subject During COVID-19 Pandemic: Pengaruh Demografi Dan Amalan Kemahiran PAK-21 Oleh Guru Pelatih Bagi Subjek Matematik Semasa Pandemik COVID-19”. Jurnal Pendidikan Sains Dan Matematik Malaysia, vol. 12, no. 1, May 2022, pp. 65-81, doi:10.37134/jpsmm.vol12.1.6.2022.