Koeswara, Sonny, and Harits Rofi Ardianto. “IMPLEMENTASI SIX SIGMA UNTUK PENINGKATAN KUALITAS SANDAL DI CV. SANCU CREATIVE INDONESIA”. SINERGI, vol. 17, no. 3, Oct. 2013, pp. 274-80, https://publikasi.mercubuana.ac.id/index.php/sinergi/article/view/781.