13. File 4640/1928 Pt 2 ‘Muscat Situation at Sur.’ Date: 1926/1931 Language: English Geographic region: SurAiqaSultanate of Muscat and Oman
14. File 4640/1928 Pt 4 ‘Muscat: Future policy in. Tariffs. (April 1932- )’ Date: 1932/1940 Language: English Geographic region: Sultanate of Muscat and Oman
15. File 4640/1928 Pt 4 ‘MUSCAT: FUTURE POLICY IN. Tariffs.’ Date: 1928/1932 Language: English Geographic region: United States of AmericaSultanate of Muscat and OmanFranceSur