Yusri, M. Y. ., S. N. . Ahmad, M. H. . Azman Ong, and N. . Khalil. “The Effectiveness of Collaborative Teaching Method in Teaching Calculus I”. Environment-Behaviour Proceedings Journal, vol. 5, no. SI1, June 2020, pp. 187-91, doi:10.21834/ebpj.v5iSI1.2319.