Parker, G.J.
Linguistic Circle of Canberra, 1970
Buku Teks SO
compiled by Howard P. McKaughan, Batua A. Macaraya
University of Hawaii Press, 1967
Buku Referensi
Steingass, F.
Gaurav Publishing House, 1986
Buku Referensi
Peter Salim
Modern English Press , 1997
Buku Referensi
Wolff, John U., compiler
Cornell University, 1972
Buku Referensi