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.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)National Council of Teachers of English. Committee on Reading Ladders for Human Relations و 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.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)National Council of Teachers of English. Committee on Reading Ladders for Human Relations و Eileen Tway. Reading Ladders for Human Relations. 6th ed. American Council on Education ; National Council of Teachers of English, 1981.