Query $16$: By using JOIN, list each author's last name, and number of books they've written.

Query $17$: By using JOIN, list the book code and book title for each book located in branch number $2$ and written by author number $20.$

Query $18$: By using JOIN, list the author's number, last name, and number of books they've written.

Query $19$: By using Left Outer Join, list all book code avaialable in branch $3$ as wells book codes that are not available in branch $3.$

Query $20$: List all book codes with more than one autohors