"by YK Kwan". chinesechinese.net. May 3, 2012. Archived from the original on May 3, 2012. Retrieved February 5, 2021.
henan.gov.cn
big5.henan.gov.cn
"中國最早金屬鑄幣 商代晚期鑄造銅貝" [China's first metal coins: copper casting in the late Shang dynasty]. henan.gov.cn (in Chinese). Archived from the original on March 17, 2012. Retrieved May 11, 2009.
"by YK Kwan". chinesechinese.net. May 3, 2012. Archived from the original on May 3, 2012. Retrieved February 5, 2021.
"中國最早金屬鑄幣 商代晚期鑄造銅貝" [China's first metal coins: copper casting in the late Shang dynasty]. henan.gov.cn (in Chinese). Archived from the original on March 17, 2012. Retrieved May 11, 2009.
