Zeller, Eduard, 1814-1908, author
Meridian Books, 1960
Buku Teks
Stanford, Michael
Blackwell Publishers, 1998
Buku Teks
Stumpf, Samuel Enoch, 1918- 1998, author
McGraw-Hill, 1999
Buku Teks
Stumpf, Samuel Enoch, 1918-1998, author
McGraw-Hill, 1989
Buku Teks
Windelband, Wilhelm, author
Dover, 1956
Buku Teks