Majid, N.A., Rainis, R. and Wan Ibrahim, W.M.M. 2017. Pemodelan Ruangan Pelbagai Jenis Kegagalan Cerun di Pulau Pinang Menggunakan Kaedah Nisbah Kekerapan: Spatial Modeling of Various Slope Failures in Pulau Pinang Using Frequency Ratio Method. GEOGRAFI. 5, 2 (Oct. 2017), 13–26.