APA

United States, . (1981). Petro-Canada, the national oil company as a tool of Canadian energy policy. [Washington, D.C: .

Chicago

United States, . 1981. Petro-Canada, the national oil company as a tool of Canadian energy policy. [Washington, D.C: .

Harvard

United States, . (1981). Petro-Canada, the national oil company as a tool of Canadian energy policy. [Washington, D.C: .

MLA

United States, . Petro-Canada, the national oil company as a tool of Canadian energy policy. [Washington, D.C: . 1981.