Shamsudin, Z. B., E. Y. Ying, and A. J. Omar. “The Safety Level Satisfaction towards Gated and Guarded Community in Malaysia”. International Review of Management and Marketing, vol. 6, no. 7S, Oct. 2016, pp. 294-8, https://www.econjournals.com/index.php/irmm/article/view/3270.