National Register of Historic Places
https://www.nps.gov/subjects/nationalregister/index.htm
National Trust for Historic Preservation
http://www.preservationnation.org/
Society of Architectural Historians
http://www.sah.org/
The World Wide Web Virtual Library:CAD
https://www.caddprimer.com/
SketchUp
Revit
https://www.autodesk.com/products/revit/overview?term=1-YEAR&tab=subscription