Ustadi, Muna Norkhairunnisak, and Nor Atiqah Mohammad Shopi. “A Study towards Implementation of Public Hub Transportation: A Case Study of Penang Central”. Journal of Transport System Engineering, vol. 2, no. 1, Mar. 2015, pp. 1-6, https://jtse.utm.my/index.php/jtse/article/view/32.