[1] 暦Wiki/米国暦 - 国立天文台暦計算室 (6/28/2019, 11:49:37 AM) https://eco.mtk.nao.ac.jp/koyomi/wiki/CAC6B9F1CEF1.html
[2] History of The Astronomical Almanac (8/10/2019, 12:01:24 PM) https://aa.usno.navy.mil/publications/docs/asa_history.php
Google search: 米国暦