Ghecham, Mahieddine Adnan. “The Impact of Informal Sector on Income Distribution: Could Concentration of Income Be Explained by the Size of Informal Sector?”. International Journal of Economics and Financial Issues, vol. 7, no. 1, Jan. 2017, pp. 594-00, https://econjournals.com/index.php/ijefi/article/view/3130.