Laetsch, W. M. (1969). The biological perspective: Introductory readings. Little.
Lua i Stíl Chicago (17ú heag.)Laetsch, Watson M. The Biological Perspective: Introductory Readings. Boston: Little, 1969.
Lua MLA (9ú heag.)Laetsch, Watson M. The Biological Perspective: Introductory Readings. Little, 1969.
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