Historical clue formulations

• Co. with a plant — 2021-01-21
• Producer: Abbr. — 2007-04-07
• Producer: Abbr. — 2007-01-09
• Plant owner: Abbr. — 2005-05-19
• Co. with a plant — 2003-12-23
• Producer: Abbr. — 2003-06-07
• Producer: Abbr. — 1999-09-12