https://brianrecipe.com/%e4%b8%ad%e7%a8%ae%e6%b3%95%e9%ba%b5%e5%9c%98%e7%99%bc%e9%85%b5%e8%88%87%e5%b7%ae%e7%95%b0-about-pre-ferment-for-bread-how-they-are-different/