https://www.cnbc.com/2017/11/29/yellen-20-trillion-national-debt-should-keep-people-awake-at-night.html https://www.reddit.com/r/news/comments/7gk1b1/federal_reserve_chair_says_us_debt_should_keep/ "I would simply say that I am very worried" Will Cryptocurrencies Make Governments and Central Banks Obsolete? https://www.youtube.com/watch?v=02Id97X_XQs