Heppenstall Company. Metallurgical Dept. (1948). Effects of alloying elements and the tensile and hardness properties of carbon and alloy steel (Rev. ed.). s.n.
Lua i Stíl Chicago (17ú heag.)Heppenstall Company. Metallurgical Dept. Effects of Alloying Elements and the Tensile and Hardness Properties of Carbon and Alloy Steel. Rev. ed. Pittsburgh: s.n, 1948.
Lua MLA (9ú heag.)Heppenstall Company. Metallurgical Dept. Effects of Alloying Elements and the Tensile and Hardness Properties of Carbon and Alloy Steel. Rev. ed. s.n, 1948.
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