《旧唐书·本纪·卷十四》
常兖任宰相时，开始制定了一个限额标准，到李泌任宰相时又衡量公事的闲散繁忙，按照公务的繁忙程度增加俸禄，当时称为 通济 ，而增加上去之后就不便削减下来。
常衮为相，始立限约，至李泌又量其闲剧，随事增加，时谓通济，理难减削。
When Chang Yan served as prime minister, he originally stipulated a limit standard; when Li Mi served as prime minister, he further examined the idleness and busyness of official positions, and increased salaries based on how busy the official position was. At that time, it was called “universal provision,” and once it was increased, it was not convenient to decrease salaries.