Related Clues:
- Prefix with friendly or system
- 'Baudolino' author
- Friendly opener?
- Environmentally friendly
- ''The Name of the Rose'' writer Umberto
- Preservation prefix
- Tourism opening
- 'The Name of the Rose' novelist Umberto
- "System" starter
- Earth (Pref.)
- ''The Island of the Day Before'' author
- Prefix for the EPA
- Prefix for physics
- Earth Day prefix
- Green prefix?