XPath challenge: can you simplify this XPath expression?

Hi Folks,

I created an XPath expression and I am wondering if it can be simplified.

The XPath expresses this:

   There must be one child Title element and
   there must be zero or more child Author elements and
   there must be one child Date element and
   nothing else.


Here's the XPath 2.0 expression I created:
  
   count(Title) eq 1 and
   count(Author) ge 0 and
   count(Date) eq 1 and
   count(*[not(name() = ('Title','Author','Date'))]) eq 0


I think this is the simplest possible XPath, but perhaps you can see a simpler expression?

/Roger