《旧唐书·列传·卷八十五》
再说鸿胪卿招待宾客、各国使节，加上回纥卖马的钱，用三分之一的赋税，也有很多赢余。何况皇上膳食和管理都极简朴，自己食用和分给百官的俸禄、伙食钱等，也没有用完，这都是皇上的私房钱。用来修理几十座宫殿也不用发愁，何况一根屋梁。 皇帝说： 经书上这么说吗？别人从来没有说过这事。 点点头罢了。又因为筹备材料建神龙寺，需要长五十尺的松木，裴延龄上奏说： 我近来在同州发现了一山谷树木，约几千棵，都长八十尺。 皇帝说： 人们说开元、天宝年间就近寻找长五、六十尺长的树木，都不容易找到，需要到岚州、胜州去购买，现在怎么这么近的地方就有这木头？ 
又因计料造神龙寺，须长五十尺松木，延龄奏曰： 臣近于同州检得一谷木，可数千条，皆长八十尺。 上曰： 人言开元、天宝中侧近求觅长五六十尺木，尚未易，须于岚、胜州采市，如今何为近处便有此木？ 
Moreover, Hongluqing entertains guests and envoys from various countries, plus the money from the Huihe selling horses, and there is still a lot of surplus with one-third of the tax. What's more, the emperor's diet and management are extremely simple, and he has not finished eating and sharing the salaries and food money of the civil and military officials. These are all the emperor's private money. It is no problem to repair dozens of palaces, let alone a house beam. The emperor said: Is this what the scriptures say? Others have never said this. Just nod. Also because of the preparation of materials for the construction of Shenlong Temple, 50-foot-long pine wood is needed, and Pei Yanling said: I recently discovered a valley of trees in Tongzhou, about thousands of them, all 80 feet long. The emperor said: It is said that during the Kaiyuan and Tianbao years, it was not easy to find trees that were 50 or 60 feet long. You need to go to Lanzhou and Shengzhou to buy them. Why are there such trees in such close proximity now?