New Day, 1976
Buku Teks
Sinco, Vicente G.
University of Philippines , 1959
Buku Teks
Francisco, Juan R., author
Linguistic Society of The Philippines, 1973
Buku Teks
Holnsteiner, Mary R., author
Community Development Research Council, 1963
Buku Teks
Amyot, Jacques
John Murray, 1939
Buku Teks