update:

added missing or better quality

ISO 2820:1974 Leather -- Raw hides of cattle and horses -- Method of trim
ISO 2820:1974/Amd 1:1996 Leather -- Raw hides of cattle and horses -- Method of trim
ISO/TR 2822-2:2017 Leather -- Raw cattle hides and calf skins -- Part 2: Guidelines for grading on the basis of mass
ISO/TR 2822-3:2017 Leather -- Raw cattle hides and calf skins -- Part 3: Guidelines for grading on the basis of defects


complete!

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