https://emmaclancy.files.wordpress.com/2018/07/apple-tax-structure-and-rate-post-2014.pdf
https://www.elibrary.imf.org/view/books/082/465808-9781513595603-en/ch002.xml
https://www.icij.org/investigations/trafficking-inc/audits-aimed-at-flagging-labor-abuses-are-designed-to-fail-investigation-finds/