1. FJ. Al-Chalabi (1981 ). "Energy and Development: Options for Global Strategies" , OPEC Seminar, OPEC Secretariat, Vienna, Austria.
2. A. Akinnusi (1969 ). Robustness oft, F andx2Tests , unpublished Master's thesis , The George Washington University, Washington DC, US.
3. RE. Ebel (1992 ). "Soviet Oil: Threat or Promise?" , Energy Watchers III, International Research Centre for Energy and Development, University of Colorado, Boulder, Colorado, US Watchers III, International Research Centre for Energy and Development, University of Colorado, Boulder, Colorado, US.