Norman Bridwell. (1997). Clifford's Spring Clean-Up (Clifford the Big Red Dog) (21st Printing.). Cartwheel.
芝加哥风格引文Norman Bridwell. Clifford's Spring Clean-Up (Clifford the Big Red Dog). 21st Printing. Cartwheel, 1997.
MLA引文Norman Bridwell. Clifford's Spring Clean-Up (Clifford the Big Red Dog). 21st Printing. Cartwheel, 1997.
警告：这些引文格式不一定是100％准确.