Hastjarjo, K., D. K. Yahya, F. Afiff, and P. Rufaidah. “Core Competence on Real Estate Industry in Globalization Phenomenon: A Contemporary Approach”. International Journal of Economics and Financial Issues, vol. 6, no. 6S, Oct. 2016, pp. 14-19, https://econjournals.com/index.php/ijefi/article/view/3103.