National Council of Teachers of English. Committee on Reading Ladders for Human Relations & Tway, E. (1981). Reading ladders for human relations (6th ed.). American Council on Education ; National Council of Teachers of English.

National Council of Teachers of English. Committee on Reading Ladders for Human Relations and Eileen Tway. Reading Ladders for Human Relations. 6th ed. Washington, D.C. : Urbana, Ill.: American Council on Education ; National Council of Teachers of English, 1981.

National Council of Teachers of English. Committee on Reading Ladders for Human Relations and Eileen Tway. Reading Ladders for Human Relations. 6th ed. American Council on Education ; National Council of Teachers of English, 1981.