Columbia subject headings:
International rivers.
Michigan northern power company.
Sault Sainte Marie canal.
St. Mary River.
Water-power.
Harvard subject headings:
International rivers.
Michigan Northern Power Company.
Saint Marys River (Mich. and Ont.)
Sault Sainte Marie Canal (Mich.)
Water-power--St. Marys River (Mich. and Ont.)
Princeton subject headings: