Hawley, Amos H.
University of Chicago Press, 1986
Buku Teks
Boughey, Arthur S.
Macmillan, 1975
Buku Teks SO
Program Pascasarjana Universitas Indonesia, 1994
Majalah, Jurnal, Buletin
Hawley, Amos H.
Ronald Press, 1950
Buku Teks SO
Zipf, George Kingsley
Hafner, 1965
Buku Teks