http://www.nhlbi.nih.gov/health/dci/Diseases/SleepApnea/SleepApnea_WhatIs.html
National Center on Sleep Disorders Research, National Heart, Lung, and Blood Institute
This brochure discusses sleep apnea and how it is treated. Sleep apnea is described here as "a serious, potentially life-threatening condition that is far more common than generally understood."