Phelps, E., Strang, R. M., & Withrow, D. (1966). Gateways to readable books: An annotated graded list of books in many fields for adolescents who find reading difficult (4th ed.). H. W. Wilson.

Phelps, Ethlyne, Ruth May Strang, and Dorothy Withrow. Gateways to Readable Books: An Annotated Graded List of Books in Many Fields for Adolescents Who Find Reading Difficult. 4th ed. New York: H. W. Wilson, 1966.

Phelps, Ethlyne, et al. Gateways to Readable Books: An Annotated Graded List of Books in Many Fields for Adolescents Who Find Reading Difficult. 4th ed. H. W. Wilson, 1966.