https://wiiw.ac.at/digital-tasks-and-ict-capital-methodologies-and-data-dlp-6429.pdf
https://www.elibrary.imf.org/view/books/082/465808-9781513595603-en/ch002.xml
https://curia.europa.eu/jcms/upload/docs/application/pdf/2021-11/cp210197en.pdf
https://files.taxfoundation.org/20211014170634/International-Tax-Competitiveness-Index-2021.pdf