Methods for Structural Stress Determination according to EN 13445-3 Annex NA – Comparison with other Codes for Unfired Pressure VesselsRalf Trieglaff, Jürgen Rudolph, Martin Beckert and Daniel FriersMATEC Web Conf., 165 (2018) 10003DOI: https://doi.org/10.1051/matecconf/201816510003