Gaya APA
Frank, M., O'Connor, J. (1999,1995,1986).
Better English Pronunciation (Ed. 2).
USA :
Cambridge University Press.
Gaya MLA
Frank, Marcella., O'Connor, J.D..
"Better English Pronunciation".
Ed. 2
USA :
Cambridge University Press,
1999,1995,1986.
Text.