Dear list,

In the _Foreign Relations of the United States_ series (a documentary
edition), a common practice in the print edition is to align the
telegram number of a diplomatic correspondence on the same line as its
dateline.  For example, on the document shown on this page
the telegram number, "2418.", is left-aligned on the *same* line as
the right-aligned dateline, "Karachi, May 15, 1956—5 p.m."

I have two questions:

1. What's the best way to describe the telegram number?  <idno
type="telegram"> or <rs type="telegram-number"> perhaps?  I'd need to
research the extent to which telegram numbers could be considered a
"formal cataloging system" as
suggests <idno> should be. <rs> seems quite broad. Is there anything
better suited to the task?

2. Is there a good way to capture the same-line-ness of these two
segments and the left-/right-alignment of this line in TEI?
Approaches I've considered include:

- A two-row table, with the left cell left-aligned and the right cell
right-aligned. But <dateline> can't be contained by a <table>, and
anyway, this feels just wrong.

- Surround the <idno> and <dateline> with <opener>, and use
CSS-inspired @style="display: inline; float: left" and -"right" for
the <idno> and <dateline> respectively.  This feels a little cleaner,
but is this the approach others would recommend?