Taylor, Richard
Englewood Cliffs : A Simon & Schuster, 1992
Buku Teks
Vaske, Martin O.
McGraw-Hill, 1963
Buku Teks
edited by Jaegwon Kim
Blackwell Publishing, 1999
Buku Teks
Loux, Michael J., author
Routledge, 2002
Buku Teks
Koons, Robert C, author
Wiley Blackwell, 2017
Buku Teks