《资治通鉴·唐纪·唐纪三十七》
再说兴庆宫与坊市居民相混杂，宫墙低矮，不是上皇所应该居住的地方。
且兴庆宫与闾阎相参，垣墉浅露，非至尊所宜居。
Moreover, Xingqing Palace is mixed with residents of 坊市, and the palace walls are low, which is not the place where Shang Huang should live.