[UPS] Journal infomation

[Mark Doyle]

Greetings,

In general, I favor a standardized way of indicating a journal reference. I  
really don't like the idea of using the Subject field for this. I also don't  
like the idea of putting 'submitted to' information in this field. Rather, it  
should only be for a peer-reviewed version of the work. It should also not  
be interpreted as meaning that the e-print and journal versions are  
identical. So we can either introduce an explicit <journalref> tag or allow a  
type attribute on a <comment> tag and explicity choose a value to indicate  
journal information:

<journalref>Phys. Rev. blah blah</journalref>

or

<comment type="journalref">Phys. Rev. blah blah</comment>

For data exchange, there is little difference between the two choices. I  
favor <journalref> myself, though using <comment> may make it more clear that  
the data may not be trustworthy.

Cheers,
Mark