《汉书·纪·昭帝纪》
经稻田使者燕仓首先发觉，迅速报告大司农杨敞，杨敞急告谏大夫杜延年，延年急奏明皇帝。
故稻田使者燕仓先发觉，以告大司农敞，敞告谏大夫延年，延年以闻。
It was first discovered by Chao Cang, an envoy from the paddy fields, who quickly reported it to the minister of agriculture, Yang Chang. Yang Chang immediately informed the Grand Court Attendant, Du Yinian, who quickly reported it to the emperor.