Historical clue formulations

• Footnote abbr. — 2021-10-03
• Endnote abbr. — 2020-03-28
• Footnote abbr. — 2018-01-10
• Footnote abbr. — 2017-09-24
• Cousin of ibid. — 2017-01-14
• Relative of ibid. — 2016-03-20
• Footnote abbr. — 2014-02-23
• Footnote abbr. — 2010-10-21
• Ibid. relative — 2008-01-26
• Footnote abbr. — 2008-01-10
• Footnote abbr. — 2004-03-18
• Ibid. relative — 2001-06-21
• Bibliographical abbr. — 2000-07-07
• Bibliography abbr. — 1999-06-02
• Footnote abbr. — 1999-01-20
• Footnote abbr. — 1997-04-26