《旧唐书·本纪·卷四》
先前这里大雨，道路不通，京师米价暴涨，官府拿出官仓粮食出卖，京师东西两市设置常平仓。
先是大雨，道路不通，京师米价暴贵，出仓粟粜之，京师东西二市置常平仓。
Heavy rains prevented access to the capital, causing the price of rice to skyrocket. The government sold grain from official storehouses, and municipal granaries were set up in the eastern and western markets of the capital.