Tidman, Paul
Wadsworth, 1999
Buku Teks SO
Hausman, Alan
Wadsworth and Cengage Learning, 2013
Buku Teks SO
Copi, Irving M.
Macmillan, 1961
Buku Teks SO
Hurley, Patrick J., 1883-1963
Wardsworth Cengage Learning, 2012
Buku Teks SO
Hurley, Patrick J., 1883-1963
Wadsworth and Cengage Learning, 2012
Buku Teks SO