^Marco de Waard (15 January 2013). Imagining Global Amsterdam: History, Culture, and Geography in a World City. Amsterdam University Press. pp. 1–. ISBN 978-90-8964-367-4. Retrieved 23 April 2013.
^Tanya Jopson (7 December 2011). Human Energy-Body Awareness: How Our Energy Body & Vibrational Frequency Create Our Everyday Life. Tanya Jopson. pp. 46–. ISBN 978-1-4663-3341-3. Retrieved 23 April 2013.