Hasibuan, M. S., S. Yasni, M. Bintang, and A. S. Ranti. “Antihyperglycemic Activity of Piper Crocatum Leaves and Cinnamomum Burmannii Bark Mixture Extract in Streptozotocin-Induced Diabetic Rats”. Journal of Mathematical and Fundamental Sciences, vol. 48, no. 2, Aug. 2016, pp. 178-91, doi:10.5614/j.math.fund.sci.2016.48.2.8.