274.    ---------------. [BÓBR, W.] [Progress in the Technique of Liquifaction of Coal.]  Przeglad gorniczo-hutniczy, vol. 30, 1938, pp. 67-78; Chem. Zentralb., 1938, II, p. 2873; Chem. Abs., vol. 34, 1940, p. 6041.

                 Review of the development of hydrogenation, low-temperature carbonization, extraction (method of Pott and Broche), the Japanese hydrogenation process, and the synthesis of hydrocarbons from CO and H₂ by the methods of Fischer-Tropsch, of Robinson-Bindley, and of the I. G. Farbenindustrie A.-G.  Considers costs of individual methods.