Hussain, Z. ., N. . Hanif, W. A. . Shaheen, and M. . Nadeem. “Empirical Analysis of Multiple Infrastructural Covariates: An Application of Gravity Model on Asian Economies”. Asian Economic and Financial Review, vol. 9, no. 3, Mar. 2019, pp. 299-17, doi:10.18488/journal.aefr.2019.93.299.317.