Septiandi, N. E. ., N. N. . Aini, and H. F. N. . Umami. “Analysis Students Mistakes of Mathematics Major of IAIN Jember in Trigonometry Operations Precondition Calculus Courses”. Proceeding International Conference on Science and Engineering, vol. 3, Apr. 2020, pp. 611-6, doi:10.14421/icse.v3.574.