Najiyyah, Amalia Nur, et al. “Effect of Variation Natrium Sitrat Concentration and Centrifugation Time on Prothrombin Time (PT) Value”. Mukhtabar : Journal of Medical Laboratory Technology, vol. 2, no. 2, Oct. 2024, pp. 46-51, doi:10.52221/mjmlt.v2i2.694.