Masrifah, M., A. Setiawan, P. Sinaga, and W. Setiawan. “An Investigation of Physics Teachers’ Multiple Representation Ability on Newton’s Law Concept”. Jurnal Penelitian & Pengembangan Pendidikan Fisika, Vol. 6, no. 1, June 2020, pp. 105 -12, doi:10.21009/1.06112.