Arikan, Fatih, et al. “Effect of Platelet-Rich Plasma on Gingival and Periodontal Ligament Fibroblasts: New in-Vitro Growth Assay”. Brazilian Journal of Oral Sciences, vol. 6, no. 23, Jan. 2016, pp. 1432-7, doi:10.20396/bjos.v6i23.8643007.