Petrov, Vladimir, author
American Institute fo Public Research, 1975
Buku Teks
edited by Keith Lehrer and Ernest Sosa
Westview Press, 1991
Buku Teks
edited by Jude Browne
Cambridge University Press, 2007
Buku Teks
Indian Committee for Cultural Freedom, 1999
Buku Teks
Outhwaite, William, author
Blackwell, 2006
Buku Teks