"Nothing in the world can take place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent."
Off the top of your head, do you know a source for that quote?
The Quotable Calvin Coolidge: Sensible Words for a New Century
Regards, Ivan