| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| Distribution and Abundance of Nonnative Plant Species at Johnstown Flood National Memorial and Allegheny Portage Railroad National Historic Site | 978-1-4921-6961-1 (1-4921-6961-7) | 2013 | National Park Service |