Liebeskind, David: "The Keys To Success"Arkiveret 5. april 2011 hos Wayback Machine, Stern Business – A publication of the Stern School of Business, New York University, efterår/vinter 2003, s. 10-15. Hentet 9. februar 2015.
web.archive.org
Liebeskind, David: "The Keys To Success"Arkiveret 5. april 2011 hos Wayback Machine, Stern Business – A publication of the Stern School of Business, New York University, efterår/vinter 2003, s. 10-15. Hentet 9. februar 2015.