Sari, sinta widya, Masthura, M. and Husnah, M. (2025) “The Effect of Variations in Cocoa Shell Carbon on the Characteristics of Environmentally Friendly Stamp Ink”, Jurnal Phi : Jurnal Pendidikan Fisika dan Fisika Terapan, 11(1), pp. 45–51. doi:10.22373/p-jpft.v11i1.20137.