APA (7th ed.) Citation

Kirkman, M., & Kirkman, L. (1988). My sister's child. Penguin Books.

Chicago Style (17th ed.) Citation

Kirkman, Maggie, and Linda Kirkman. My Sister's Child. Australia: Penguin Books, 1988.

MLA (9th ed.) Citation

Kirkman, Maggie, and Linda Kirkman. My Sister's Child. Penguin Books, 1988.