[1] The Symmetry010 Calendar, Dr. Irv Bromberg, University of Toronto, Canada, 2022-07-04T12:42:32.000Z, 2023-07-04T13:14:54.731Z http://individual.utoronto.ca/kalendis/classic.htm

[2] The Symmetry454 Calendar, Dr. Irv Bromberg, University of Toronto, Canada, 2022-06-28T03:54:45.000Z, 2023-07-04T13:21:59.536Z http://individual.utoronto.ca/kalendis/symmetry.htm

[4] Symmetry Calendar Date Conversion Sheets, Dr. Irv Bromberg, University of Toronto, Canada, 2019-05-17T05:11:42.000Z, 2023-07-04T14:26:57.999Z http://individual.utoronto.ca/kalendis/convert/index.html

[5] Symmetry454 and Symmetry010 Calendar FAQs - Symmetry454-Calendar-FAQs.pdf, 2020-05-01T22:29:07.000Z, 2023-07-04T14:28:50.292Z http://individual.utoronto.ca/kalendis/Symmetry454-Calendar-FAQs.pdf

[6] Symmetry454 Calendar Birthdays, Holidays and Events - Symmetry454-Events.pdf, 2019-08-15T23:54:17.000Z, 2023-07-04T14:31:38.464Z http://individual.utoronto.ca/kalendis/Symmetry454-Events.pdf

[3] この著者のサイトでは両暦法やヘブライ暦改良案とグレゴリオ暦の併記で更新日時が書かれています。

[7] New Year’s Revolution - University of Toronto Magazine, 2023-07-04T14:37:09.000Z https://magazine.utoronto.ca/research-ideas/culture-society/irv-bromberg-symmetry454-new-calendar-idea/

[8] What is Irvember?, Dr. Irv Bromberg, University of Toronto, Canada, 2012-05-17T03:34:03.000Z, 2023-07-04T14:37:51.290Z http://individual.utoronto.ca/kalendis/irvember.htm