Berlanda, Toma
Routledge, 2014
Buku Teks SO
White, Edward T., author
Florida University, [19?-]
Buku Teks
Ramsey, Charles George, 1884-1963, author
John Wiley & Sons, 2000
Buku Teks
Ramsey
John Wiley & Sons, 1994
Buku Referensi
edited by Joseph N. Boaz
John Wiley & Sons, 1970
Buku Referensi