I found this on Agilent web page at Helpful Resources "EA-4/02 Released in December 1999, this is a comprehensive (79 pages) and authoritative publication (from Europe's official accreditation organisation). Other than price (FREE), what makes this especially valuable is the number of examples that are used to illustrate the uncertainty budgeting process."
This publication is distributed using the Adobe Acrobat portable document format but if your browser doesn't already have the (free) viewer installed, you'll need to download and install it first. Acrobat reader