| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Great Natural Areas of Eastern Pennsylvania | 978-0-8117-2574-3 (0-8117-2574-X) | 1996 |
| Great Natural Areas of Western Pennsylvania | 978-0-8117-2778-5 (0-8117-2778-5) | 2000 |
S.J. · S.O. · S Ostrander · Stephen J. · Stephen Ostrander