Historical clue formulations

• X-ray units — 2026-02-15
• X-ray doses — 2025-04-20
• Exposure units — 2024-02-09
• Dosimeter units — 2019-10-18
• X-ray units — 2019-08-30
• They may be high in a fallout zone — 2017-06-11
• Dosimeter reading — 2016-08-18
• CAT scan units — 2016-08-13
• Physics units — 2016-04-24
• X-ray units — 2015-06-22
• Exposure units — 2013-10-09
• X-ray units — 2013-05-14
• Units of a dangerous dosage — 2012-10-30
• X-ray units — 2012-06-26
• X-ray units — 2011-11-20
• Dosimeters measure them — 2010-06-11
• X-ray dosage units — 2010-03-24
• Dosage units — 2010-03-19
• X-ray units — 2008-05-18
• X-ray doses — 2007-11-25
• CAT scan units — 2007-06-10
• X-ray units — 2007-02-26
• Physics units also known as centigrays — 2006-11-30
• Units of 100 ergs per gram — 2006-06-10
• X-ray units — 2006-05-15
• Dosage units — 2006-04-16
• Exposure units — 2005-08-14
• X-ray doses — 2003-02-16
• Units of 100 ergs/gram — 2001-06-30
• Dangerous dosage units — 2001-05-04
• Physics units — 1998-12-06
• X-ray units — 1998-09-23
• Physics units — 1998-02-17
• X-ray units — 1995-08-16
• Dosimeters measure them — 1995-08-11