Ardiyani, F., and S. Pancaningtya. “Morphological Variation of Somatic Embryos of Coffea Arabica L. During Some Sub-Culture Periods”. Pelita Perkebunan (a Coffee and Cocoa Research Journal), Vol. 33, no. 2, Aug. 2017, pp. 97-08, doi:10.22302/iccri.jur.pelitaperkebunan.v33i2.263.