Al-Badran, Adnan, and Sabaa Al-Fadal. 2017. “Cloning, Expression of Hirudin Gene from Leech (Hirudo Orientalis) in BL21(DE3) Strain”. American Scientific Research Journal for Engineering, Technology, and Sciences 27 (1):25-42. https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/2511.