1. See for example: United Nations Statistical Office World Energy Supplies 1955-58 Basic Statistics of Energy for O.E.E.C. 1950-57 1958
2. For Canadian data the most useful starting point is: Dominion Bureau of Statistics - Industry and Merchandising Division: Guide to D.B.S. Sources of Information about Fuel and Electricity 1958
3. George , P. Céographie de l' énergie 1950
4. Energy or Everyman;Warren;The B.C. Professional Engineer,1953
5. Miller , E. W. Regional Differences in Primary Energy Sources for the Generation of Electricity in Pennsylvania