
https://www.diw.de/documents/publikationen/73/diw_01.c.670904.de/19-31-3.pdf

https://static1.squarespace.com/static/5afc0bbbf79392ced8b73dbf/t/5b07d7ce1ae6cf2a4178f587/1527240672975/SGC_Full_Report.pdf

https://itep.org/amazon-in-its-prime-doubles-profits-pays-0-in-federal-income-taxes/