Al-Motarreb, Ahmed; Baker, Kathryn; Broadley, Kenneth J. (2002). “Khat: Pharmacological and Medical Aspects and Its Social Use in Yemen”. 《Phytotherapy Research》 16 (2): 403–13. doi:10.1002/ptr.1106. PMID12203257.
Al-Motarreb, Ahmed; Baker, Kathryn; Broadley, Kenneth J. (2002). “Khat: Pharmacological and Medical Aspects and Its Social Use in Yemen”. 《Phytotherapy Research》 16 (2): 403–13. doi:10.1002/ptr.1106. PMID12203257.