APA   Click to copy
Gross, J. (2010). Social Networking Websites: A Virtual Playground for Genealogists. Pastfinder.

Chicago/Turabian   Click to copy
Gross, James. “Social Networking Websites: A Virtual Playground for Genealogists.” Pastfinder, 2010.

MLA   Click to copy
Gross, James. “Social Networking Websites: A Virtual Playground for Genealogists.” Pastfinder, vol. 21, 2010, pp. 12–13.

@misc{gross2010a,
  title = {Social Networking Websites: A Virtual Playground for Genealogists},
  year = {2010},
  journal = {Pastfinder},
  pages = {12--13},
  volume = {21},
  author = {Gross, James}
}