^What Is Cancer?. National Cancer Institute. 2007-09-17 [2017-11-26]. (原始内容存档于2015-04-09) (英语). 本文含有此来源中属于公有领域的内容。
^Wilson, Kathleen Atkins; Waugh, Anne; Chambers, Graeme; Grant, Allison; Ross, Janet. Ross and Wilson anatomy and physiology in health and illness. Edinburgh: Churchill Livingstone. 2006: 53–54. ISBN 0-443-10101-9.
^Nunn, Laura Silverstein; Silverstein, Alvin; Silverstein, Virginia B. Cancer. Brookfield, Conn: Twenty-First Century Books. 2006: 11–12. ISBN 0-7613-2833-5.