| title | ISBN-13 | year of publica- tion | other author(s) |
|---|---|---|---|
| Essentials of Physical Geography | 978-0-03-022909-1 | 1998 | Robert E. Gabler · Daniel Wise · James F. Petersen · Robert Gabler |
| Holt Eastern Hemisphere People, Places, and Change Main Idea Activities: An Introduction to World Studies | 978-0-03-068164-6 | 2003 | |
| Modern Earth Science | 978-0-03-050609-3 | 1998 | W. Ramsey · C. Phillips · F. Watenpaugh |
| People, Places, and Change | 978-0-03-053652-6 | 2003 | |
David Helgren Robert Sager · Prof. Robert J. Sager · R. S. · R. Sager · Robert J. Sager · Robert S.