totalling a group of worksheets

[iguana2go]

I want to create a summary worksheet which will total, say, worksheets
between a sheet called 'start' and a sheet called 'end' without typing the
individual sheet names, so that I can then insert sheets between those called
start and end without redoing the formula in my summary sheet. something
like
=sum(start!A3:end!A3)
but this doesn't work ... I know it can be done because i've done it before
I just can't work out how to do it now

 

[Fred Smith]

This way:
=sum(start:end!A3)

Regards,
Fred