1. 06Hey: E. Heyn and O. Bauer, “Copper and Sulfur”,Metallurgie, 3, 73–82 (1906) in German. (Equi Diagram; Experimental)
2. 13Bor: K. Bornemann and K. Wagenmann, “Electroconductivity of Metallic Alloys in Liquid State”,Ferrum, 11, 276–282 (1913); 11, 293–294 (1914), quoted in [Hansen]. (Equi Diagram; Experimental)
3. 13Fri: K. Friedrich and M. Waehlert, “Investigation of Systems with Layer Formation. II. Copper-Copper Sulfide”,Metall. u. Erz., 10, 976–979 (1913) in German. (Equi Diagram; Experimental)
4. 15Pos: E. Posnjak, E.T. Allen, and H.E. Merwin,Econ. Geol., 10, 491–535 (1915);Z. Anorg. Allg. Chem., 94, 95–138 (1916) in German. (Equi Diagram; Experimental)
5. 29Jou: J.G. Joukoff, “On the Solubility of Cu-Sulfides in Cu-S at High Temperatures”,Metall. u. Erz., 26, 137–141 (1929) in German. (Equi Diagram; Experimental)