REMS
4 letters
Historical clue formulations
- Radiation units — 2020-03-22
- Sleep phenomena — 2017-07-21
- Sleep stages — 2015-11-01
- Dream states, for short — 2014-07-16
- Sleep stages — 2012-04-29
- Phenomena after retiring — 2010-04-09
- Bedtime phenomena — 2010-01-21
- Radiation units — 2009-01-12
- Radiation units — 2005-10-23
- Sleep activities — 2004-01-30
- Radiation measures — 2003-08-19
- Radiation units — 2003-06-11
- Radiation dosages — 2002-03-24
- Sleep phenomena — 1999-01-03
- Sleep phenomena — 1998-08-09
- Sleep phenomena — 1998-07-07
- Radiation units — 1997-07-30
- X-ray measurements — 1995-12-26
- Dream states — 1994-08-13
- Dream stages — 1994-03-06