US5064733-A  Bonanos, N., Ellis, B., Knight, K. S., and Mahmood, M. N., "Ionic Conductivity of Gadolinium-Doped Barium Cerate Pervskites," Solid State IonicsL, 35 (1989) pp. 179-188.;  Bonanos, N., Ellis, B., and Mahmood, M. N., "Oxide Ion Conduction in Ytterbium-Doped Strontium Cerate," Solid State IonicsL, 28-30 (1988), pp. 579-584.;  Cook, R. L., McDuff, R. C., and Sammells, A. F., "Electrochemical Reduction of Carbon Dioxide to Methane at High Current Densities," J. Electrochem. Soc., 134 1873 (Jul. 1987).;  Dewulf, D. W. and Bard, A. J., "The Electrochemical Reduction of CO()2 to CH()4 and C2 H()4 at Cu/NAFION Electrodes (Solid Polymer Electrolyte Structures)," Cat. Lett. 1, 73-80, (1988).;  Frese, Jr., K. W. and Leach, S., "Electrochemical Reduction of Carbon Dioxide to Methane, Methanol, and CO on Ru Electrodes," J. Electrochem. Soc., 132, 259 (1985).;  Handbook of Batteries and Fuel CellsL , Ed. David Linden, 43-26 to 43-33, published by McGraw-Hill Book Company(1984).;  Hori, Y., Kikuchi K., Murata, A., and Suzuki, S., "Production of Methane and Ethylene in electrochemical Reduction of Carbon Dioxide at Copper Electrode in Aqueous Hydrogencarbonate Solution," Chem. LettL ., 897 (1986).;  Hori, Y., Kikuchi, K., and Suzuki, S., "Production of CO and CH()4 in Electrochemical Reduction of CO()2 at Metal Electrodes in Aqueous Hydrogencarbonate Solution," Chem LettL ., 1695 (1985).;  Hori, Y., Murata, A., Takahashi, R., and Suzuki S., "Enhanced Formation of Ethylene and Alcohols at Ambient Temperature and Pressure Electrochemical Reduction of Carbon Dioxide at a Copper Electrode," J. Chem. Soc., Chem. CommunL ., 17, 1988.;  Hori, Y., Murata, A., Takahashi, R., and Suzuki, S., "Electro-reduction of CO to CH()4 and C2 H()4 at a Copper Electrode in Aqueous Solutions at Ambient Temperature and Pressure," J. Am. Chem. Soc., 109, 5022 (1987).;  Hori, Y., Murata, A., Takahashi, R., and Suzuki, S., "Electrochemical Reduction of Carbon Monoxide to Hydrocarbons at Various Metal Electrodes in Aqueous Solution," Chem. LettL ., 1665 (1987).;  Iwahara H., Uchida, H., Ono, K., and Ogaki, K., "Proton Conduction in Sintered Oxides Based on BaCeO()3I ," J. Electrochem. Soc.L : Solid-State Science and Technology, pp. 529-533 (FEB. 1988).;  Iwahara, H., Uchida, H., and Yamasaki, I., "High-Temperature Steam Electrolysis Using SrCeO3 -Based Proton Conductive Solid Electrolyte," Int. J. Hydrogen EnergyL , vol. 12, No. 2, pp. 73-77.;  Keller, G. E., and Bhasin, M. M., "Synthesis of Ethylene via Oxidative Coupling of Methane," Journal of CatalysisL, 73, 9-19 (1982).;  Lin, C., Campbell, K. D., Wang, J., and Lunsford, J. H., "Oxidative Dimerization of Methane over Lanthanum Oxide," J. Phys. Chem., 90, 534-537 (1986).;  Osuka, K., Liu, Q., Hatano, M. and Morikawa, A., "Synthesis of Ethylene by Partial Oxidation of Methane over the Oxides of Transition Elements with LiCl," Chemistry LettersL , The Chemical Society of Japan, 903-906 (1986).;  Otsuka, K., Jinno, K., and Morikawa, A., "The Catalysts Active and Selective in Oxidative Coupling of Methane," Chemistry LettersL , The Chemical Society of Japan, 499-500 (1985).;  Otsuka, K., Liu, Q., and Morikawa, A., "Selective Synthesis of Ethylene by Partial Oxidation of Methane over LiCl-Sm2 O()3I ," J. Chem. Soc., Chem. Commun., 586-587 (1986).;  Otsuka, K., Yokoyama, S., and Morikawa, A., "Catalytic Activity-and Selectivity-Control for Oxidative Coupling of Methane by Oxygen-Pumping through Yttria-Stabilized Zirconia," Chemistry LettersL , The Chemical Society of Japan, 319-322 (1985).;  Petrova, G. N., and Efimova, O. N., ElektrokhimiyaL , 19(7) 978 (1983).;  Scherban, T., and Nowick, A. S., "Bulk Protonic Conduction in Yb-Doped SrCeO()3I ," Solid State IonicsL , 35 (1989) pp. 189-194.;  Seimanides, S. and Stoukides, M., "Electrochemical Modification of Ag-MgO Catalyst Electrodes during Methane Oxidation," J. Electrochem. Soc.L , 1535-1536, Jul., 1986.