Pancaningtyas, Sulistyani. 2015. “The Effect of 2,4 Dichlorophenoxyacetic Acid on in Vitro Callogenesis of Cocoa (Theobroma Cacao L.)”. Pelita Perkebunan (a Coffee and Cocoa Research Journal) 31 (2), 90-98. https://doi.org/10.22302/iccri.jur.pelitaperkebunan.v31i2.67.