Posted: January 6, 2020
•http://www.ideafinder.com/history/
•http://totallyabsurd.com
•http://inventors.about.com/library/bl_by_state_inventors.htm
•http://www.enchantedlearning.com/inventors/usonly.shtml
•http://www.teacheroz.com/inventors.htm
•http://inventionreaction.com
•http://greatachievements.org
• https://www.historylearningsite.co.uk/inventions-and-discoveries-of-the-twentieth-century/inventions-1900-to-1990/
