المصادر WILLIAMS, Colin C. et SCHNEIDER, Friedrich. The shadow economy. London, Institute of Economic Affairs, 2013. MAURIN, Alain; SOOKRAM, Sandra; WATSON, Patrick Kent. Measuring the Size of the Hidden Economy in Trinidad&Tobago. Economic Measurement Unit, Dept of Economics, University of the West Indies, St Augustine, Trinidad and Tobago, January, 2003.‏https://ecomod.net/sites/default/files/document-conference/ecomod2003/Maurin.pdf  FELD, Lars P.; FREY, Bruno S. Tax compliance as the result of a psychological tax contract: The role of incentives and responsive regulation. Law & Policy, 2007, 29.1: 102-120.‏ https://www.zora.uzh.ch/id/eprint/2305/2/2007_FreyB_Law-and-Polic_Tax-Complianc-2.pdf World Happiness Report 2020 https://happiness-report.s3.amazonaws.com/2020/WHR20.pdf  Wiles, David. Why Swedes are okay with paying taxes - Sweden.se https://sweden.se/society/why-swedes-are-okay-with-paying-taxes/W   https://ar.sweden.se/society/corruption/ https://sweden.se/society/why-swedes-are-okay-with-paying-taxes/ https://www.weforum.org/agenda/2019/11/income-tax-around-the-world/ لقاء خاص مع الرئيس المدير العام لوكالة أناب السيد العربي ونوغي .. أسرار خطيرة حول أناب تكشف لأول مرة https://www.youtube.com/watch?v=7c1ymH8ao5s&t=1s كيف ننجح في محاربة الفساد ؟ التجربة السويدية https://youtu.be/BK4TB0MvbGg