Scarpe, N. V., author
Unesco, 1951
Buku Referensi
edited by Merlin C. Wittrock; a project of the American Educational Research Association
Macmillan Library Reference USA, 1986
Buku Referensi
Canobbio, Mary M., author
Mosby, 1996
Buku Teks
Munadi Patmadiwira
Fakultas Sastra UI, 1978
Buku Teks
Parrish, Betsy, author
McGraw-Hill , 2004
Buku Teks