The eBook copy of this book is not guaranteed to include any supplemental materials. Typically, only the book itself is included. This is true even if the title states it includes any access cards, study guides, lab manuals, CDs, etc.
The workbook for HOW 13 provides reinforcement for the major principles contained in the reference manual. This expanded supplement contains exercises that are coordinated specifically with sections in HOW 13 and are designed to provide students with realistic learning applications, not just isolated sentence exercises.