2019 · Omar, Mohamad Firdaus, Mohamad, Nuriah, et al. · The International Islamic University Malaysia Repository (The International Islamic University Malaysia) · 1
2020 · Mohamad Firdaus Omar, Nuriah Mohamad, et al. · The International Islamic University Malaysia Repository (The International Islamic University Malaysia)
2019 · Fathilah binti Ali, Mohamad Firdaus Omar · Chemical and Natural Resources Engineering Journal (Formally known as Biological and Natural Resources Engineering Journal)