Prior to development of the Isartor Test Suite, the PDF/A Competence Center Technical Working Group (TWG) led the way in development of best practices and other tools to support ISO standards for mainstream PDF technology.
Between April, 2007 and March of 2008 the PDF/A TWG produced the following six Technical Notes, available to all at no charge. In 2014 these Notes are generally accepted best-practice among PDF/A vendors.
Technical Notes 0001 and 0003 were addressed in the 1st corrigendum to ISO 19005-1, and are thus now part of PDF/A itself.
Technical Notes 0004, 005 and 0007 were partially developed but were never published.