Ingpen, Robert
Encyclopedia of ideas that changed the world : the greatest discoveries and inventions of human history
Dragon's World, 1993
 Buku Referensi
Berlin, Isaiah
Against the current: essays in the history of ideas
Viking Press, 1981
 Buku Teks SO
Smith, Samuel
Ideas of the great educators
Barnes & Noble Books, 1979
 Buku Teks
Tsanoff, Radoslav A.
The great philosophers
Harper & Brothers, 1953
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Hyde, William De Witt
The five great philosophies of life
Macmillan, 1959
 Buku Teks SO