How to get a copy of accompanying CD to a Book purchased in iBooks

I recently purchased a book which has an accompanying CD. If I purchased the hard copy of the book from a book store, the CD would've been bundled along with the book. Seen as I purchased my copy on iBooks I don't have a CD.The book is an educational book so all the example data, solutions and case studies referenced in the book are on the CD. How do I get my copy of the CD?