Martin, Samuel E.
Tuttle Company, 1956
Buku Teks
Alfonso, Anthony, author
Sophia University LL Center of Applied Linguistics, 1980
Buku Teks
Sato, Eriko, author
Wiley, 2002
Buku Teks
Mohamad Ryan Saputra, author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2015
UI - Skripsi Membership
Charles E. Tutle Co.Inc, 1959,
Buku Referensi