Abu Fayyad, Khaled, et al. “A Theoretical and Empirical Discussion on Environmental Awareness Issue in Malaysia: Establishing a Viable Research Framework”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 30, no. 4, Dec. 2016, pp. 318-34, https://www.gssrr.org/JournalOfBasicAndApplied/article/view/6547.