text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE table_29087004_3 (written_by VARCHAR, directed_by VARCHAR, united_states_original_airdate VARCHAR)
  ### Question:
  Who were the writers of the episodes directed by Greg Sullivan and which first aired on July 21, 2012?
  ### Answer:
  SELECT written_by FROM table_29087004_3 WHERE directed_by = "Greg Sullivan" AND united_states_original_airdate = "July 21, 2012"