Gaya APA

Powell, G, R. et al (2011). ROI of social media : how to improve the return on your social marketing investment . USA: John Wiley & Sons.

Gaya MLA

Powell, Guy, R.. et al. "ROI of social media : how to improve the return on your social marketing investment". USA: John Wiley & Sons, 2011. Buku/Printed Material.