Historical clue formulations

• Cocktails made with ginger beer, informally — 2022-05-08
• Stubborn sorts — 2015-07-29
• See 26-Across — 2014-12-20
• Some slippers — 2012-07-01
• Slippers of sorts — 2005-01-12
• Open-back shoes — 2004-10-10
• Drug smugglers — 2002-02-17
• Sterile hybrids — 2002-01-06
• Obstinate ones — 2001-05-21
• Plow pullers — 2000-11-26
• Symbols of stubbornness — 1999-03-09
• Stubborn beasts — 1998-11-24
• Slippers for the stubborn? — 1994-09-14