APA (7th ed.) Citation

Blyton's, E. (1991). The O'Sullivan Twins. Budget Books.

Chicago Style (17th ed.) Citation

Blyton's, Enid. The O'Sullivan Twins. Australia: Budget Books, 1991.

MLA (9th ed.) Citation

Blyton's, Enid. The O'Sullivan Twins. Budget Books, 1991.

Warning: These citations may not always be 100% accurate.