Noor Afifah Wan Ahmad, W., Firdaus Sufahani, S., Abd Hakim Mohamad, M., SaifullahRusiman, M., Zulariffin Md Maarof, M. and Ali lmran Kamarudin, M. 2023. NON-CLASSICAL OPTIMAL CONTROL PROBLEM: A CASE STUDY FOR CONTINUOUS APPROXIMATION OF FOUR-STEPWISE FUNCTION. Advances in Differential Equations and Control Processes. 30, 4 (Sep. 2023).