Universitas Indonesia, 2006
UI - Skripsi (Membership)
Raykov, Tenko, author
Routledge, Taylor & Francis Group, 2008
Buku Teks
Tabachnick, Barbara G., author
Allyn and Bacon, 2001
Buku Teks
Gnanadesikan, Ram, 1932-, author
John Wiley & Sons, 1977
Buku Teks
Cooley, William W., author
John Wiley & Sons, 1971
Buku Teks