Columbia subject headings:
Electric utilities--Canada.
Electric utilities--United States.
Interconnected electric utility systems--Canada.
Interconnected electric utility systems--United States.
Harvard subject headings:
Electric utilities--Canada.
Electric utilities--United States.
Interconnected electric utility systems--Canada.
Interconnected electric utility systems--United States.
Princeton subject headings:
Electric utilities--Canada.
Electric utilities--United States.
International interconnected electric utility systems--Canada.
International interconnected electric utility systems--United States.