Faridah, A., Holinesti, R. and Syukri, D. (2015) “Betalains from Red Pitaya Peel (Hylocereus polyrhizus): Extraction, Spectrophotometric and HPLC-DAD Identification, Bioactivity and Toxicity Screening”, Pakistan Journal of Nutrition, 14(12), pp. 976–982. doi:10.3923/pjn.2015.976.982.