Anatomy of the Heart Quiz retrieved from:
http://www.purposegames.com/game/anterior-view-of-the-heart-quiz#

YouTube EKG tracing video retrieved from:
https://www.youtube.com/watch?v=4vkbywows-o

YouTube EKG Interpretation video retrieved from::
https://www.youtube.com/watch?v=LEaRyzudjw4

EKG Rhythms and Interpretation Strips retrieved from:
http://acls-algorithms.com/rhythms/