Pandiangan, D. (2011) “Perubahan Morfologi dan Anatomi Kalus Catharanthus roseus dengan Perlakuan Triptofan (The morphological and anatomical changes on tryptophan-treated callus of Catharanthus roseus)”, JURNAL BIOS LOGOS, 2(1). doi: 10.35799/jbl.2.1.2012.379.