APA (7th ed.) Citation

Bull, P., & Kamionkowski, M. (2013). What if Planck's Universe isn't flat?

Chicago Style (17th ed.) Citation

Bull, P., and M. Kamionkowski. What If Planck's Universe Isn't Flat? 2013.

MLA (9th ed.) Citation

Bull, P., and M. Kamionkowski. What If Planck's Universe Isn't Flat? 2013.

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