Usually a combination of a C-1 visa and D visa is required. E visa Treaty Trader (E-1 visa) and Treaty Investor (E-2 visa) visas are issued to citizens of countries that have signed treaties of commerce and navigation with the United States. They are issued to individuals working in businesses engaged in substantial international trade or to investors (and their employees) who have made a 'substantial investment' in a business in the United States. The variant visa issued only to citizens of Australia is the E-3 visa (E-3D visa is issued to spouse or child of E-3 visa holder and E-3R to a returning E-3 holder). F visa These visas are issued for foreign students enrolled at accredited US institutions. F-1 visas are for full-time students, F2 visas are for spouses and children of F-1 visa holders and F-3 visas are for "border commuters" who reside in their country of origin while attending school in the United States. They are managed through SEVIS. G visa G visas are issued to diplomats, government officials, and employees who will work for international organizations in the United States. The international organization must be officially designated as such. The G-1 visa is issued to permanent mission members; the G-2 visa is issued to representatives of a recognized government traveling temporarily to attend meetings of a designated international organization; the G-3 visa is issued to persons who represent a non-recognized government; the G-4 visa is for those who are taking up an appointment; and the G-5 visa is issued to personal employees or domestic workers of G1–G4 visa holders. G1–G4 visas are also issued to immediate family members of the principal visa holder, if they meet certain criteria. NATO visa Officials who work for the North Atlantic Treaty Organization require a NATO visa. The NATO-1 visa is issued to permanent representatives of NATO and their staff members, NATO-2 visa is issued to a representative of member state to NATO or its subsidiary bodies, advisor or technical expert of the NATO delegation visiting the United States, a member of the NATO military forces component or a staff member of the NATO representative, NATO-3 visa is issued to official clerical staff accompanying the representative of a NATO member state, NATO-4 visa is issued to foreign national recognized as a NATO official, NATO-5 visa is issued to a foreign national recognized as a NATO expert and NATO-6 visa