Here you can find articles from relevant specialist journals that go deeper into certification topics from an expert point of view.

Certification of New Technology
by Jannemann, T; John, Manfred; as presented at the World Certification Conference 2003 in Tokyo

Applying the EC Pressure Equipment Directive in the Gas Industry
by Büschel, K.; John, M.; Wasser, U., in: gwf-Gas/Erdgas 141 (2000) No. 2