Firmanto, H., Kumalasari, Y. and Muarrofah, Z. (2021) “Determination of Cocoa Powder Quality Produced by Small-Medium Enterprise Using Six Sigma Analysis”, Pelita Perkebunan (a Coffee and Cocoa Research Journal), 37(2), pp. 137-145. doi: 10.22302/iccri.jur.pelitaperkebunan.v37i2.480.