suchen [und] SGB RO 91-[123][0123456789][0123456789][0123456789]* or RO 91-4[012345678][0123456789][0123456789]* or RO 91-49[012345678][0123456789]* or RO 91-499[0123456789]* or RO 91-0[123456789][0123456789][0123456789]* or RO 91-00[123456789][0123456789]* or RO 91-000[123456789]*