The Universal Business Language (UBL) Guidelines for Customization Version 1.0 provides practical information for creating UBL-conformant and UBL-compatible document schemas. This public review ends 29 Nov.

If you are involved in implementing UBL then your comments on these guidelines would be most appreciated.

http://docs.oasis-open.org/ubl/guidelines/UBL-Customization1.0prd01.pdf

For the official announcement see:

http://lists.oasis-open.org/archives/tc-announce/200809/msg00010.html