[1] 
[CITE@ja[[[沈徳符]] - Wikipedia]], [TIME[2023-04-29T14:19:17.000Z]], [TIME[2023-05-13T14:19:23.551Z]] <https://ja.wikipedia.org/wiki/%E6%B2%88%E5%BE%B3%E7%AC%A6>

[2] [CITE[历代正闰考_百度百科]]
([TIME[2023-05-13T14:20:41.000Z]])
<https://baike.baidu.com/item/%E5%8E%86%E4%BB%A3%E6%AD%A3%E9%97%B0%E8%80%83/8450509?fr=aladdin>

[3] [CITE@en[Li dai zheng run kao : si juan | Library of Congress]]
([TIME[2023-05-13T14:21:04.000Z]])
<https://www.loc.gov/item/2014514145>

[4] [CITE@en[Li dai zheng run kao : si juan - Juan 1 | Library of Congress]]
([TIME[2023-05-13T14:33:36.000Z]])
<https://www.loc.gov/resource/lcnclscd.2014514145.1A001/?st=slideshow>