International Society for Educational Information
ISEI, 1987
Buku Teks
Cobban, Alfred, author
Braziller, 1965
Buku Teks
Teeuw, A. (Andries), 1921-, author
Martinus Nijhoff, 1979
Buku Teks
Hoffding, Harold, author
Dover, 1955
Buku Teks
Virtue and Company Limited , 1977
Buku Teks