Oil Shale--an Impending Energy Source.
J Petrol Technol 1972 Nov; :1325-1330
Recent political, technical, and economic developments lead to optimism for the commercial exploitation of oil shale as a source of energy. Although presently the production of oil by mining or aboveground retorting seems feasible, the production of oil by in situ techniques or of pipeline gas by either aboveground or underground gasification is less probable for a while.
J. Petrol. Technol., November 1972, PP. 1325-1330