Hegel, George Wilhelm Friedrich
Boss-Merrill, 1953
Buku Teks
Dunford, Nelson
John Wiley & Sons, 1976
Buku Teks
Sykes, Percy Molesworth
Macmillan and co., limited, 1930
Buku Teks
Lesesne, J. Mauldin
University of South Carolina Press , 1970
Buku Teks
Cambridge University Press, 1978
Buku Teks