Jordan Georgiev Deliversky,  Smuggling of Migrants as an Influential Factor on National Security, Economic and Social Life.   journal   = {International Journal of Humanities and Social Sciences}, [online]. World Academy of Science, Engineering and Technology.
    February 2017, vol. 123(3). 693 - 696
    [viewed 24 January 2021]. Available from: https://publications.waset.org/pdf/10006747.