Excel 2003 file header/trailer bytes?
 

I was interested in identifying Excel files (for recovering lost
files). I had a look at some Excel 97-2003 workbooks, and they begin:
D0CF11E0A1B11AE1 (hexadecimal)
Now I download a 250-page document from openoffice.org purporting to be
Microsoft Excel File Format
but it does not show this string of bytes as the "beginning of file"
I hoped to find out what bytes indicate the end of an Excel file.
Many file formats do have some footer/trailer bytes, and I wished
to know what is the end of an Excel file looks like. I could look
at some files with a hex editor, but is there an authoritative
reference for this at Microsoft?