Each publisher has a unique name; a telephone number and a Contact Person. The contact person has a first and last name. A publisher publishes one or more books; a book is published by exactly one publisher. A book is identified by its ISBN, and other attributes are title, Last name of the first author, price, and a number of pages. Each book is written by one or more authors, but there may be books with unknown authors. An author writes one or more books, potentially for different publishers. Each author is uniquely described by an author ID, and we know each author's name address and DOB. Notice that every author may have multiple addresses each composed of Street, Number, City, and State. For each book that each author publishes he reaches an agreement with the publisher's office and based on this, the author is paid a certain royalty percentage on each book he or she authors, which is different for each book and for each author. An author then receives a separate royalty check for each book he or she writes. Each check is identified by its check number, and we also keep track of the date and amount of each check. A book can be part of a series. Each series is identified by a series id and described by a name, description and year of the first release. One book can belong to several series, and a series consists of at least one but potentially many books. Some series may require the books to be accessed in a specific order and this order should be stored in the database. Finally, each book can have any number of previous editions and can be a previous edition to any number of books.