R.S. · R. Sager · Robert J. Sager · Robert S.
| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Essentials of Physical Geography | 978-0-03-022909-1 (0-03-022909-X) | 1998 | Robert E. Gabler · Daniel Wise · James F. Petersen · Robert Gabler |
| Modern Earth Science | 978-0-03-050609-3 (0-03-050609-3) | 1998 | W. Ramsey · C. Phillips · F. Watenpaugh |