Benjamin's library book

Benjamin checked out a new book from the school library. Tuesday is library day for both Benjamin and Heather. Today, he came home with Bunnicula. I told him that there were two other books in that series; Howliday Inn, and The Celery Stalks at Midnight. He turned to a page just after the title page and said "Hey, there are two more! Nighty-Nightmare and Return to Howliday Inn." I didn't know there were more to the series. Now, I want to read these books. I told Benjamin that he had to check them out next so I could read them, and he told me that the library only has Bunnicula. I am bummed out! Maybe Santa will have to bring a boxed set for Christmas!