EP1648816-A2  See references of WO 2005005032A2;  MORENO J A ET AL: "n-Butane isomerization over transition metal-promoted sulfated zirconia catalysts: effect of metal and sulfate content", APPLIED CATALYSIS A: GENERAL, ELSEVIER SCIENCE, AMSTERDAM, NL, vol. 210, no. 1-2, 9 March 2001 (2001-03-09), pages 151-164, XP004272616, ISSN: 0926-860X, DOI: DOI:10.1016/S0926-860X(00)00802-4;  See also references of WO 2005005032A2WO2005005032-A3  See also references of EP 1648816A2;  See also references of EP 1648816A4EP2452915-A1  OHTSUKA H: "The selective catalytic reduction of nitrogen oxides by methane on noble metal-loaded sulfated zirconia", APPLIED CATALYSIS B: ENVIRONMENTAL, AMSTERDAM, NL, vol. 33, 1 January 2001 (2001-01-01), pages 325-333, XP002228705, DOI: 10.1016/S0926-3373(01)00190-4;  D. S. NEWSOM CATAL. REV. vol. 21, 1980, page 275;  H. TOPSOE; M. BOUDART J. CATAL. vol. 31, 1973, page 346EP2452916-A1  OHTSUKA H: "The selective catalytic reduction of nitrogen oxides by methane on noble metal-loaded sulfated zirconia", APPLIED CATALYSIS B: ENVIRONMENTAL, AMSTERDAM, NL, vol. 33, 1 January 2001 (2001-01-01), pages 325-333, XP002228705, DOI: 10.1016/S0926-3373(01)00190-4;  D. S. NEWSOM CATAL. REV. vol. 21, 1980, page 275;  H. TOPSOE; M. BOUDART J. CATAL. vol. 31, 1973, page 346EP1648816-B1  MORENO J A ET AL: "n-Butane isomerization over transition metal-promoted sulfated zirconia catalysts: effect of metal and sulfate content", APPLIED CATALYSIS A: GENERAL, ELSEVIER SCIENCE, AMSTERDAM, NL, vol. 210, no. 1-2, 9 March 2001 (2001-03-09), pages 151-164, XP004272616, ISSN: 0926-860X, DOI: DOI:10.1016/S0926-860X(00)00802-4EP2452916-B1  OHTSUKA H: "The selective catalytic reduction of nitrogen oxides by methane on noble metal-loaded sulfated zirconia", APPLIED CATALYSIS B: ENVIRONMENTAL, AMSTERDAM, NL, vol. 33, 1 January 2001 (2001-01-01), pages 325-333, XP002228705, DOI: 10.1016/S0926-3373(01)00190-4EP2452915-B1  OHTSUKA H: "The selective catalytic reduction of nitrogen oxides by methane on noble metal-loaded sulfated zirconia", APPLIED CATALYSIS B: ENVIRONMENTAL, AMSTERDAM, NL, vol. 33, 1 January 2001 (2001-01-01), pages 325-333, XP002228705, DOI: 10.1016/S0926-3373(01)00190-4