Norman Bridwell. (1997). Clifford's Spring Clean-Up (Clifford the Big Red Dog) (21st Printing.). Cartwheel.
Chicago-referens (17:e uppl.)Norman Bridwell. Clifford's Spring Clean-Up (Clifford the Big Red Dog). 21st Printing. Cartwheel, 1997.
MLA-referens (9:e uppl.)Norman Bridwell. Clifford's Spring Clean-Up (Clifford the Big Red Dog). 21st Printing. Cartwheel, 1997.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.