YAMAMURA MASAMI ET AL: 'Oxidative coupling of methane over alkali halide-promoted perovskite oxide catalysts', APPL CATAL A GEN; APPLIED CATALYSIS A:GENERAL AUG 18 1994 ELSEVIER SCIENCE PUBLISHERS B.V., AMSTERDAM, NETH, vol. 115, no. 2, 18 August 1994 (1994-08-18), pages 269 - 283, XP001183331