Analysis of information sources in references of the Wikipedia article "720s BC" in English language version.
6 Yan 鄢 was located north of present-day Yanling County 鄢陵縣, Henan.{...}LORD YIN 1 (722 BCE) ANNALS{...}In summer, in the fifth month, the Liege of Zheng overcame Duan (Gongshu Duan) at Yan.6
鄭伯克段于鄢{...}鄢,鄭國邑名,在今河南鄢陵北。
6 Yan 鄢 was located north of present-day Yanling County 鄢陵縣, Henan.{...}LORD YIN 1 (722 BCE) ANNALS{...}In summer, in the fifth month, the Liege of Zheng overcame Duan (Gongshu Duan) at Yan.6