https://www.researchgate.net/profile/Nigel-Cory/publication/340114267_Why_Countries_Should_Build_an_Interoperable_Electronic_Invoicing_System_Into_WTO_E-Commerce_Negotiations/links/5e795fe8299bf1b2b9ac05c2/Why-Countries-Should-Build-an-Interoperable-Electronic-Invoicing-System-Into-WTO-E-Commerce-Negotiations.pdf