Calc: external references of multiple files; extend selection

Hi all,

I write my invoices in Calc (daggy I know) all saved as individual files, and I’m doing a summary Calc of all my invoices.

So in my summary file, I’ve got external references to each individual invoice, and referencing to my Date, Client, Job Title and $Total cells. These cell locations don’t change in each invoice.

Each invoice file is “Invoice 2014-xxx.ods” where xxx is incremented with each invoice.

Now that I’ve got my first couple of lines populated with the cells from the first few invoices, how can I do extend selection so the file number portion of the reference increments, instead of the row number (standard behaviour).

Where do I put ‘$’ into the reference so I get the behaviour I need, instead of having to manually edit each line?

[a little more…]
So far, I’ve tried Edit>Fill>Series which only works on the resultant output, not the reference formula
The simplest is to have $ everywhere in the reference, ie eg,
=‘file:///D:/invoices/Invoice 2014-001.xls’#$Invoice.$E$13
CTRL+copy down all my columns, then search and replace the “-001.” with incrementing “-xxx.” for each row.
Slow, but reliable.

An easier, lazier method of doing this would be much appreciated!

Thanks in advance,