https://www.ifs.org.uk/uploads/Presentations/Carl%20Emmerson%2C%202017%20General%20Election%2C%20manifesto%20analysis%2C%20opening%20remarks.pdf
http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6438&CESifoWP.search=+
https://verfassungsblog.de/the-rise-and-fall-of-world-constitutionalism/