《资治通鉴·后晋纪·后晋纪四》
又设立信箱，让人投入匿名信相互告发，以至有人因而被族灭全家的。
又置函，使人投匿名书相告讦，至有灭族者。
The letterbox was set up again, allowing people to post anonymous letters to accuse each other, so that some people were wiped out as a result.