Kendrick, Corrinne W. "Knife Case." U. S. Patent number: 2528059. Washington, DC: United States Patent and Trademark Office, 1948. http://www.uspto.gov/patft/index.html (18 February 2008).

Kendrick, Corrinne W. "Knife Case." U. S. Patent number: 2528059. Washington, DC: United States Patent and Trademark Office, 1948. http://www.uspto.gov/patft/index.html (18 February 2008).