Levy, R. L., & Mathers, J. A. L. (1949). Relationship Between the Oxygen Saturation of the Blood and Changes in the Electrocardiogram, Blood Pressure and Heart Rate During Induced Anoxemia: Observations on Normal Persons and Patients with Suspected and Manifest Coronary Heart Disease.

Levy, Robert L., and James A. L. Mathers. Relationship Between the Oxygen Saturation of the Blood and Changes in the Electrocardiogram, Blood Pressure and Heart Rate During Induced Anoxemia: Observations On Normal Persons and Patients With Suspected and Manifest Coronary Heart Disease. 1949.

Levy, Robert L., and James A. L. Mathers. Relationship Between the Oxygen Saturation of the Blood and Changes in the Electrocardiogram, Blood Pressure and Heart Rate During Induced Anoxemia: Observations On Normal Persons and Patients With Suspected and Manifest Coronary Heart Disease. 1949.