By Serious Eats[0], founded by former New York Times food editor Ed Levine. Also by the BBC[1]. Arsicault Bakery in SF was named the best bakery in America by Bon Appetit. Tartine Bakery is a James Beard winner.

[0] http://www.seriouseats.com/2013/08/taste-test-the-best-sourd...

[1] http://www.bbc.com/travel/story/20131121-flour-power-in-san-...