bibliomixed and extendedlink

I've just been looking at some XML coming in from a typesetter and noticed some misuse of <extendedlink> elements. Looking at what they were trying to do led me to suspect they should have been using a simple <link> element. Of course, these aren't allowed within bibliomisc elements. 

So, is there a particular reason why <extendedlink> is allowed within <bibliomisc> when <link> isn't?

cheers

nic

--

Nic Gibson
Corbas Consulting
Digital Publishing Consultancy and Training
http://www.corbas.co.uk, +44 (0)7718 906817