Crawford, M. H. (n.d.). Heart. In World Book Online. Retrieved May 31, 2010,
     from worldbookonline.com...
       This article covers the basic biology of the heart and its many cellular
       constituents. The heart is a large organ responsible for circulating
       blood within the human body. Placed in the center of the chest, it weighs
       anywhere from 19 grams in a baby to 312 grams in an adult. The heart is
       surrounded by a membrane called the epicardium, which is additionally
       surrounded by another membrane called the Pericardium, allowing for
       additional protection and ease of motion. Continuing on, the article
       covers every aspect of the heart including its chambers, valves, blood
       vessels, circulation of blood, and afflictions and diseases. Many of the
       dieseases and/or afflictions include atherosclerosis, cardiac
       arrhythmia's, heart attacks, septal defects, cardiomyopathy, inflammatory
       heart disease, and heart failure. Also covering the history of heart
       research, the article covers the very beginning of knowledge with the
       diagnosis of affliction based on heart beat by the Chinese to the
       discovery of arteries and veins by physician Andreas Vesalius in the mid
       1500's. Moving on, this source also documented the development of heart
       surgery, with a timeline of the progression of events that occurred
       leading up to the first successful heart transplant in 1967 by a team of
       south American physicians. Overall, this source was valuable in providing
       basic knowledge of the heart and its many ailments. This information will
       help in the future with applying stem cell research to diseases and
       abnormalities many people face today.