Sinaga, Parlindungan, Andi Suhandi, and . Liliasari. 2014. “Improving the Ability of Writing Teaching Materials and Self-Regulation of Pre-Service Physics Teachers through Representational Approach”. International Journal of Sciences: Basic and Applied Research (IJSBAR) 15 (1):80-94. https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/2084.