Ruhlmann, William James (1991). Chicago Group Portrait (Box Set) (Media notes). New York City, NY: Columbia Records. p. 5. Archived from the original(CD booklet archived online) on September 30, 2017. Retrieved November 13, 2017.
Ruhlmann, William James (1991). Chicago Group Portrait (Box Set) (Media notes). New York City, NY: Columbia Records. p. 5. Archived from the original(CD booklet archived online) on September 30, 2017. Retrieved November 13, 2017.