APA (7th ed.) Citation

Blettner Maria, Zeeb Hajo, & Merzenich Hiltrud. (2010). Decreasing sperm quality: A global problem? BMC.

Chicago Style (17th ed.) Citation

Blettner Maria, Zeeb Hajo, and Merzenich Hiltrud. Decreasing Sperm Quality: A Global Problem? BMC, 2010.

MLA (9th ed.) Citation

Blettner Maria, et al. Decreasing Sperm Quality: A Global Problem? BMC, 2010.