Popper, Karl R., author
Routledge, 1961
Buku Teks
edited by H. Aram Veeser
Routledge, 1989
Buku Teks
edited and introduced by Richard Wilson and Richard Dutton
Longman, 1992
Buku Teks
[Cambridge University Press, ], 2012
eBooks
Popper, Karl R., author
Routledge & Kegan Paul, 1972, c. 1969
Buku Teks