Subject
- Trade (practice)18
- Astronomy, Medieval17
- Frontiers17
- Pharmacology--Early works to 180017
- Territorial disputes17
- Air services agreements16
- Harbours16
- Military operations16
- Visits16
- Concessions, Oil, Qatar15
- Military art and science -- Early works to 180015
- Slavery15
- State visits15
- Boundary disputes14
- Concessions, Oil, Kuwait14
- Passports14
- Piracy14
- Territorial waters14
- Treaty of Friendship, Commerce and Navigation between Great Britain and Muscat (1939)14
- Armed forces13