Badan Rehabilitasi dan Rekonstruksi NAD-Nias, 2009
Buku Teks
Fira Basuki, author
Grasindo, 2003
Buku Teks
Dyah Rinni, author
Falcon Publishing, 2016
Buku Teks
edited by John J. Marchalonis
John Wiley & Sons, 1982
Buku Teks
Briggs, Asa
Longman, 1974
Buku Teks