Jayawardane, C., and J. C. Edirisinghe. “Environmental Stringency and Dirty Exports: An Empirical Analysis”. International Journal of Economic Practices and Theories, vol. 4, no. 6, Dec. 2014, pp. 1018-23, http://ijept.eu/index.php/ijept/article/view/Environmental_Stringency_and_Dirty_Exports_an_Empirical_Analys.