Database: books
Question: List down the ISBN of the books purchased by the customer with an email of fsier3e@ihg.com.
SQL: SELECT T1.isbn13 FROM book AS T1 INNER JOIN order_line AS T2 ON T1.book_id = T2.book_id INNER JOIN cust_order AS T3 ON T3.order_id = T2.order_id INNER JOIN customer AS T4 ON T4.customer_id = T3.customer_id WHERE T4.email = 'fsier3e@ihg.com'