Brief Citation: Otake et al, Pen Points for Writing Instruments (1976)
Full Citation: Otake, Nobuyuki, Kozo Ando, and Hironobu Hori. "Pen Points for Writing Instruments." U. S. Patent number: 4076428. Washington, DC: United States Patent and Trademark Office, 1976. http://www.uspto.gov/patft/index.html (25 April 2007).
