May 11, 1991
Certificate with decorative blue border and text: "Awarded to Linus C. Pauling, Ph.D., In Recognition of his outstanding world-wide achievements in investigating the benefits to humanity of Vitamin C. This Award is given this 11th day of May in the year 1991 at The Second World Congress on Vitamin C and the Immune System. May 10, 11, 12, San Diego, California."
Awarded by the Second World Congress on Vitamin C.
Subject: Medical sciences
Name: Second World Congress on Vitamin C