A. R. A. Laksono, Y. Martono, and C. A. Riyanto, “Protoporphyrin IX Extraction from Quail Eggshell (Cortunix cortunix) and Its Complexity with Zn(II)”, EKSAKTA: J. Sci. Data Anal., vol. 18, no. 2, pp. 155–166, Sep. 2018.