L. H. Al-Ttaffi, H. Abdul-Jabbar, and S. A. Bin-Nashwan, “The Role of Income Tax System Structure in Tax Non-Compliance Behaviour Among SMEs in Yemen”, IJBF, vol. 16, no. 2, pp. 23 – 49, Jun. 2021, doi: 10.32890/ijbf2021.16.2.2.