Norman Bridwell. (1997). Clifford's Spring Clean-Up (Clifford the Big Red Dog) (21st Printing.). Cartwheel.
Chicago-viite (17. p.)Norman Bridwell. Clifford's Spring Clean-Up (Clifford the Big Red Dog). 21st Printing. Cartwheel, 1997.
MLA-viite (9. p.)Norman Bridwell. Clifford's Spring Clean-Up (Clifford the Big Red Dog). 21st Printing. Cartwheel, 1997.
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