Can anyone help me solve a simple but annoying problem?

I have a formula that links to a URL

='http://www.domain.com/18 Apr 2007/[results.xls]results'!$D$2

which gives back the value 3 (as it should)

Now I want to draw 18 Apr 2007 from a cell value found in an open file
called reference.xls.

So I tried

="'http://www.domain.com/" &'[reference.xls]sheet1'!$A$53
&"/[results.xls]results'!$D$2"

but it just shows the words

'http://www.domain.com/18 Apr 2007/[results.xls]results'!$D$2

instead of the value

Can anyone tell me the right syntax please?

many thanks

tp