As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.
— Albert Einstein

Personal beauty is a greater recommendation than any letter of reference.
Aristotle reference quote

I learned how fast you can go from being an international hero to being a reference in a joke on a late night talk show.
— Michael Phelps

Praise invariably implies a reference to a higher standard.
— Aristotle

Referring to the bad sun conditions in left field at the stadium: It gets late out there early.
— reference quotation by Yogi Berra