XML question

As I continue to shine an Yttrium lamp* on my ignorance, can I ask - 
does a ref attribute on an XML element take a single URI or can it take 
a white space separated list??


* I learnt yesterday that the rare earth element Yttrium is used in 
powerful projector lamps as used at cinemas and was keen to get it into 
the conversation somehow.

Received on Wednesday, 23 April 2008 10:16:33 UTC