Summers on the FED

http://www.washingtonpost.com/blogs/wonkblog/wp/2017/08/25/lawrence-summers-the-case-for-janet-yellen/

Similarly judgments about bubbles need to be reached in the context of the level of neutral rates. Levels of price-earning ratios that would have looked bubbly with a 2 percent neutral real rate are much less so with a zero neutral real rate.