《资治通鉴·唐纪·唐纪五十七》
谏官很久无人在内殿奏论朝政，穆宗听到郑覃等人的进言后，觉得十分惊讶，他对宰相说： 这几个都是什么人？ 宰相回答说： 是谏官。 
时久无阁中论事者，上始甚讶之，谓宰相曰： 此辈何人？ 对曰： 谏官。 
For a long time, there have been no remonstrance officers submitting memorials and discussing state affairs in the imperial palace. Muzong was amazed to hear the comments of Zheng Tan and his colleagues, and he said to the prime minister, "Who are those people?" The prime minister replied, "Remonstrance officers."