- Massachusetts Historical Commission (MACRIS)
- National Register of Historic Places
- Preservation MASS
- Preservation MASS Burial Grounds
- National Trust for Historic Preservation
- Historic New England
- Merrimack Valley Preservation Group
- National Park Service — Secretary of Interior’s Standards for Rehabilitation, Preservation Briefs
- The Old House Web
- Old House Journal
- This Old House
- PreservationWeb
- Sunday Drives, Merrimack Valley 1988-1999
- Andover Center for History and Culture
