Dopp, K. E. (1906). The later cave-men. Rand, McNally & Co..
Lua i Stíl Chicago (17ú heag.)Dopp, Katharine Elizabeth. The Later Cave-men. Chicago: Rand, McNally & Co., 1906.
Lua MLA (8ú heag.)Dopp, Katharine Elizabeth. The Later Cave-men. Rand, McNally & Co., 1906.
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