"Invasive Species". New Hampshire Dept. of Agriculture. Archived from the original on 7 November 2012. Retrieved 22 October 2013.
nps.gov
Swearingen, J.; Reshetiloff, K.; Slattery, B.; Zwicker, S. (2002). "Norway Maple". Plant Invaders of Mid-Atlantic Natural Areas. National Park Service and U.S. Fish & Wildlife Service. Archived from the original on 2003-03-17.
Swearingen, J.; Reshetiloff, K.; Slattery, B.; Zwicker, S. (2002). "Norway Maple". Plant Invaders of Mid-Atlantic Natural Areas. National Park Service and U.S. Fish & Wildlife Service. Archived from the original on 2003-03-17.
"Invasive Species". New Hampshire Dept. of Agriculture. Archived from the original on 7 November 2012. Retrieved 22 October 2013.