APA   Click to copy
Young, J. K., & Dugan, L. (2014). Survival of the fittest: Why terrorist groups endure. Perspectives on Terrorism, 8, 2–23.

Chicago/Turabian   Click to copy
Young, Joseph K, and Laura Dugan. “Survival of the Fittest: Why Terrorist Groups Endure.” Perspectives on Terrorism 8 (2014): 2–23.

MLA   Click to copy
Young, Joseph K., and Laura Dugan. “Survival of the Fittest: Why Terrorist Groups Endure.” Perspectives on Terrorism, vol. 8, 2014, pp. 2–23.

@article{young2014a,
  title = {Survival of the fittest: Why terrorist groups endure},
  year = {2014},
  journal = {Perspectives on Terrorism},
  pages = {2-23},
  volume = {8},
  author = {Young, Joseph K and Dugan, Laura}
}