CASSIDY, J., ROETTGER, D., & WIXSON, K. K. (1987). Climb the hills. Scribner Educational Publishers.

CASSIDY, Jack, Doris ROETTGER, and Karen K. WIXSON. Climb the Hills. New York: Scribner Educational Publishers, 1987.

CASSIDY, Jack, et al. Climb the Hills. Scribner Educational Publishers, 1987.