British Standards Institution. (1970). Method for Rockwell superficial hardness test (N and T scales). British Standards Institution.
Lua i Stíl Chicago (17ú heag.)British Standards Institution. Method for Rockwell Superficial Hardness Test (N and T Scales). London: British Standards Institution, 1970.
Lua MLA (8ú heag.)British Standards Institution. Method for Rockwell Superficial Hardness Test (N and T Scales). British Standards Institution, 1970.
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