Baker, Ann
Tree or three? : an elementary pronunciation course
Cambridge University Press, 1982
 Buku Teks SO
Baker, Ann
Introducing English pronunciation : a teacher's guide to Tree or Three? and Ship or Sheep?
Cambridge University Press, 1982
 Buku Teks SO
Potapova, Nina F.
Russian elementary course; Book 1
Foreign Languages Publishing House, 1959
 Buku Teks SO
Potapova, Nina F.
Russian : elementary course book II
Foreign Languages Publishing House, 1959
 Buku Referensi
McKeague, Charles P., 1946-
Elementary and intermediate algebra : a combined course
Brooks/Cole Cengage Learning, 2012
 Buku Teks SO