APA (7th ed.) Citation

Ziefert, H., & Barroux. (2013). It's time to say goodnight (First edition.). Blue Apple Books.

Chicago Style (17th ed.) Citation

Ziefert, Harriet, and Barroux. It's Time to Say Goodnight. First edition. Maplewood, NJ: Blue Apple Books, 2013.

MLA (8th ed.) Citation

Ziefert, Harriet, and Barroux. It's Time to Say Goodnight. First edition. Blue Apple Books, 2013.

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