Electrocardiogram (ECG or EKG): References

American Heart Association. (2012). Electrocardiogram (ECG or EKG). Retrieved 02/08/2015 from http://www.heart.org/HEARTORG/Conditions/HeartAttack/SymptomsDiagnosisofHeartAttack/Electrocardiogram-ECG-or-EKG_UCM_309050_Article.jsp.

Gantz, L. (2012). Electrocardiography. Goldman’s Cecil Medicine; 54, 272-278. Philadelphia: Elsevier Saunders.