CREATE TABLE table_28688313_1 (written_by VARCHAR, us_viewers__in_millions_ VARCHAR)

Who wrote the episode with 7.52 million US viewers?
SELECT written_by FROM table_28688313_1 WHERE us_viewers__in_millions_ = "7.52"
SELECT "written_by" FROM "table_28688313_1" WHERE "7.52" = "us_viewers__in_millions_"