What is the entry for Upper index Kcal/ Nm 3 for the row with an entry that has a Lower index MJ/ Nm 3 of 47.91, and an Upper index MJ/ Nm 3 larger than 53.28?
CREATE TABLE "wobbe_index_of_common_fuel_gases" (
  "fuel_gas" text,
  "upper_index_kcal_nm_3" real,
  "lower_index_kcal_nm_3" real,
  "upper_index_mj_nm_3" real,
  "lower_index_mj_nm_3" real
);
SELECT SUM("upper_index_kcal_nm_3") FROM "wobbe_index_of_common_fuel_gases" WHERE "lower_index_mj_nm_3"=47.91 AND "upper_index_mj_nm_3">53.28;