Pancaningtyas, S. “The Effect of 2,4 Dichlorophenoxyacetic Acid on in Vitro Callogenesis of Cocoa (Theobroma Cacao L.)”. Pelita Perkebunan (a Coffee and Cocoa Research Journal), Vol. 31, no. 2, Aug. 2015, pp. 90-98, doi:10.22302/iccri.jur.pelitaperkebunan.v31i2.67.