Al-Shatari, Sahar Abdul Hassan, et al. “Practice and Opinion of Doctors in Primary Health Care Centers Toward Referral System: Samples from Nine Governorates in Iraq”. AL-Kindy College Medical Journal, vol. 17, no. 2, Aug. 2021, pp. 100-6, https://doi.org/10.47723/kcmj.v17i2.296.