《汉书·传·王贡两龚鲍传》
臣下听说古时候军队平常每日行进三十里，为吉事而行进也衹五十里。《诗经》有云： 彼风疾发，彼车疾驰，环顾周道，心中哀伤。 
臣闻古者师日行三十里，吉行五十里，《诗》云： 匪风发兮，匪车揭兮，顾瞻周道，中心怛兮。 
The minister heard that in ancient times, the army usually marched thirty miles a day, and for auspicious events, it was only fifty miles. In the "Book of Songs", it says: The wind is blowing fast, the car is speeding, looking around the main road, my heart is sad.