How many books has Sara Shepard written?

1. Pretty little liars
2. Flawless
3. Perfect
4. Unbelievable
5. Wicked
6. Killer
7. Heartless
8. Wanted
9. Twisted
10. Ruthless
11. Stunning
12. Title Unknown

*This is the Pretty Little Liars series but she has written a lot more books.