Herve Abdi, author
Oxford University Press, 2009
Buku Teks
Michael S. Lewis-Beck, editor
Sage Publications, Topan Publishing, 1993
Buku Referensi
Finney, D.J.
1955
Buku Teks
Bambang Prasetyo, author
RajaGrafindo Persada, 2007
Buku Teks
Kendall, Maurice, Sir, author
Charles Griffin, 1975
Buku Teks