Sandhi Nugraheni, Anna Fitriawati, and Bagas Ardiyantoro, “Optimization And Stability Testing Of Avocado Leaf (*Persea americana*) Extract Soap Formulated With A Combination Of VCO, Palm Oil, And Olive Oil Using The Simplex Lattice Design Method”, IJHET, vol. 5, no. 3, Sep. 2026.