Ball-point. Types, basic parameters and technical requirements
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Fountain-pens. Types, basic parameters and technical requirements
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Mechanical pencils. Types, basic parameters and technical requirements
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Ball-point. Nodes for writing. Specification
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Writing units designed for boll-point pens. General specifications
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Ink for stationery. Specification
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Fountain-pens. General specifications
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Ball-point. General specifications
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Mechanical pencils. Part 2. Black leads. Classification and dimensions
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