* Kierszenbaum, A.L. (2007). Histology and cell biology: an introduction to pathology (2nd edición). Mosby Inc. ISBN 0-3230-4527-8
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* Shakespeare, William. Hamlet Complete, Authoritative Text with Biographical and Historical Contexts, Critical History, and Essays from Five Contemporary Critical Perspectives. Boston: Bedford Books of St. Martins Press, 1994, p. 50.
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== Bibliografia ==
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* Argente, Horacio (2009). Semiología médica: enseñanza basada en el paciente. Panamericana. ISBN 978-950-06-0072-9.
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Oxford English Dictionary
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* Klabunde, R.E. (2005). Cardiovascular physiology concepts. Lippincott Williams & Wilkins. ISBN 0-7817-5030-X