p. 21نسخة محفوظة 10 November 2015 على موقع واي باك مشين. Inside the human body: using scientific and exponential notation. Author: Greg Roza. Edition: Illustrated. Publisher: The Rosen Publishing Group, 2007. (ردمك 978-1-4042-3362-1), (ردمك 978-1-4042-3362-1). Length: 32 pages
p. 21نسخة محفوظة 10 November 2015 على موقع واي باك مشين. Inside the human body: using scientific and exponential notation. Author: Greg Roza. Edition: Illustrated. Publisher: The Rosen Publishing Group, 2007. (ردمك 978-1-4042-3362-1), (ردمك 978-1-4042-3362-1). Length: 32 pages
Dominance and the evolution of sexual dimorphism in human voice pitch Puts, David Andrew and Gaulin, Steven J.C and Verdolini, Katherine; Evolution and Human Behavior, ISSN1090-5138, 2006, Volume 27, Issue 4, pp. 283–96