DVS 2906-1975 Resistance roller seam welding of overlapping parts
DVS 2907-1975 "Recommendations for the selection and comparison of spot welding machines, projection and seam welding machines (single-phase alternating current)"
DVS 2908-1975 "Measuring in spot welding, projection welding and seam welding"
DVS 2913-1978 "Guidelines for measurements at single-phase spot welding machines, projection seam and seam welding machines"