1. ISO 6520: 1992, Classification of imperfections in metallic fusion welds, with explanations.
2. ISO 5817: 1992, Arc-welded joints in steel — Guidance on quality levels for imperfections.
3. NF E 52-109–1: 1990, Lifting and handling — Welded joints — Part 1: Fabrication.
4. EUROCODE 3 (1992 version), Design of Steel Structures — Chapter 9: Fatigue.