The Release 12.1.3 OA Framework Developer's Guide (MOS Note 1107973.1) contains many links to the BLAF UI Guidelines posted on OTN at (as of 2010):
These links are now broken again. Is it possible to restore the BLAF UI Guidelines to OTN?
This link works fine:
BLAF Guidelines - Specifications
As does this:
BLAF Guidelines - Ancillary Graphic List (Repository)
The link you provided had a superfluous underscore which caused the 404.