Black, C.E., author
Alfred A. Knopf, 1966
Buku Teks
Tietz, Jurgen, 1964-, author
H.F. Ullmann, 2013
Buku Teks
Burickson, Sherwin, author
Philosophical Library, 1959
Buku Referensi
MacMillan St Martin's Press, 1953
Buku Referensi
edited by Brian Hunter
Macmillan, 1991
Buku Referensi