Suparno, M. I. . Hamim, and H. Prasetiawan. “ANALISIS PENGENDALIAN KUALITAS PRODUKSI BOGIE BARBER S2HD9C MENGGUNAKAN METODE LEAN SIX SIGMA DI PT BARATA INDONESIA (PERSERO) GRESIK”. Journal of Research and Technology, vol. 2, no. 2, Dec. 2016, pp. 32-46, doi:10.55732/jrt.v2i2.235.