1. Kokkola, Tom. 2010. The Payment System: Payments, Securities and Derivatives, and the Role of the Eurosystem. Frankfurt am Main: European Central Bank.
2. European Central Bank. 2017. ECB Payment Statistics. Frankfurt am Main: European Central Bank.
3. Federal Reserve Board. 2017. The Federal Reserve Payments Study—2016. Washington, DC: Federal Reserve Board.
4. The World Bank. 2017. DataBank. Washington, DC: World Bank Group.
5. Council of the European Union and European Parliament. 2015. Regulation (EU) 2015/751 of the European Parliament and of the Council—of 29 April 2015—on Interchange Fees for Card-Based Payment Transactions. Official Journal of the European Union 123: 1–15.