“Morphological Characterization and Identification of Coffea Liberica Callus of Somatic Embryogenesis Propagation”. Pelita Perkebunan (a Coffee and Cocoa Research Journal), vol. 31, no. 2, Aug. 2015, pp. 81-89, https://doi.org/10.22302/iccri.jur.pelitaperkebunan.v31i2.168.