CREATE TABLE "see_also" (
  "name" text,
  "birth_year_and_age" text,
  "net_worth_us_billions" real,
  "citizenship" text,
  "source" text
);

Question: What's the source of wealth of the person worth $17 billion?
SQL: SELECT "source" FROM "see_also" WHERE "net_worth_us_billions"=17;