Gaya APA
L.G.Alexander, (1977).
QUESTION AND ANSWER GRADED ORAL COMPREHENSION EXERCISES (New Edition).
Yogyakarta:
Longman Group UK Limited.
Gaya MLA
L.G.Alexander, .
"QUESTION AND ANSWER GRADED ORAL COMPREHENSION EXERCISES".
New Edition
Yogyakarta:
Longman Group UK Limited,
1977.
Buku Inti.