Nurwahidah, Bahri M, Rahim A. A comparative study of Hilbert transform and Fourier transform methods to complex-based global minimum variance portfolio. Stat., optim. inf. comput. [Internet]. 2025Jul.22 [cited 2025Oct.14];14(3):1270-95. Available from: http://47.88.85.238/index.php/soic/article/view/2586