Quoted in Bob Smizik, "Cow-kicked: FSN fires Lange as Penguins' TV voice", http://www.post-gazette.com/pg/06181/702334-61.stm Pittsburgh Post-Gazette (2006-06-30)
According to Smizik in Tales from the Pittsburgh Penguins http://books.google.com/books?id=v6VbC6CRWTsC&pg=PA103&lpg=PA103&dq=%22He+beat+him+like+a+rented+mule.%22&source=web&ots=60xyCcZKrt&sig=M8tqlcsQykyW9zqmIIZQE4Zkjug&hl=en&sa=X&oi=book_result&resnum=3&ct=result#PPA103,M1 (Sports Publishing, 2006, ISBN 10:1582611998), Lange credits a Pittsburgh mall security guard with giving him the phrase. After giving Lange directions to a location in the building, the guard gave him a piece of paper with the phrase written down on it.