http://en.wikipedia.org/wiki/Roentgen_equivalent_man
It's not authoritative, but if you really want to dig in to the issue the references at the end of the article are a good place to start.
http://en.wikipedia.org/wiki/Roentgen_equivalent_man
It's not authoritative, but if you really want to dig in to the issue the references at the end of the article are a good place to start.