Niazi, A. A., and W. M. Shoukat. “Intravenous Patients Controlled Analgesia Versus Maxillary Nerve Block in Unilateral Maxillary Surgery”. Anaesthesia, Pain & Intensive Care, Jan. 2019, pp. 112-7, https://mail.apicareonline.com/index.php/APIC/article/view/303.