Table schema:
CREATE TABLE Documents (document_name VARCHAR, template_id VARCHAR); CREATE TABLE Templates (template_id VARCHAR, template_type_code VARCHAR)

Question: Show all document names using templates with template type code BK.
SQL: SELECT T2.document_name FROM Templates AS T1 JOIN Documents AS T2 ON T1.template_id = T2.template_id WHERE T1.template_type_code = "BK"