Palmer, B. W. (1988). Guide and index to the papers of Charles Sumner. Chadwyck-Healey.
Lua i Stíl Chicago (17ú heag.)Palmer, Beverly Wilson. Guide and Index to the Papers of Charles Sumner. Alexandria, VA: Chadwyck-Healey, 1988.
Lua MLA (8ú heag.)Palmer, Beverly Wilson. Guide and Index to the Papers of Charles Sumner. Chadwyck-Healey, 1988.
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