I just read an article from Yitang Zhang's little sister (in Chinese). It touched my soul. A must-read (translated from Chinese using Google translation): https://zhishifenzi-com.translate.goog/depth/character/480.h...

Part of the translation is not so perfect and you have to use your best guess sometimes. The Chinese version is a masterpiece.

In addition, here is an article from Yitang Zhang's PhD advisor. Not so nice: https://www.math.purdue.edu/~ttm/ZhangYt.pdf