Roze, Maris
Prentice-Hall, 2002
Buku Teks
Springer Nature Singapore, 2019
eBooks
Novianti Suhendar Putri
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2007
UI - Skripsi (Membership)
edited by Anne E. Baker and Kees Hengeveld
Wiley-Blackweell, 2012
Buku Teks
edited by Archibald A. Hill
Voice of America, 1969
Buku Teks