Lammers, W. J. (2005). Fundamentals of behavioral research William J. Lammers, Pietro Badia. Thomson Wadsworth.
Lua i Stíl Chicago (17ú heag.)Lammers, William J. Fundamentals of Behavioral Research William J. Lammers, Pietro Badia. Thomson Wadsworth, 2005.
Lua MLA (8ú heag.)Lammers, William J. Fundamentals of Behavioral Research William J. Lammers, Pietro Badia. Thomson Wadsworth, 2005.
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