Columbia subject headings:
Espionage, East Indian--Canada.
Sikhs--Canada.
Terrorism--India.
Harvard subject headings:
Aircraft accidents--History--20th century.
Bombings--Canada--History--20th century.
Canada--Relations--India.
India--Relations--Canada.
India. Intelligence Bureau--History--20th century.
Punjab (India)--Politics and government.
Sikhs--Canada--Politics and government.
Terrorism--Canada--Accidents--History--20th century.
Princeton subject headings: