Hutagaol, R.P. and Niken, N. 2017. VALIDASI METODE PENETAPAN KADAR CYANOCOBALAMIN SECARA SPEKTROFOTOMETRI VISIBEL DOUBLE BEAM. Sains Natural: Journal of Biology and Chemistry. 2, 1 (Nov. 2017), 24–34. DOI:https://doi.org/10.31938/jsn.v2i1.32.