Fermi's Mystery Sources: Methods for Classification and Association
  Unassociated Fermi-LAT sources provide a population with discovery potential. We discuss efforts to find new source associations for this population, and summarize the successes to date. We discuss how the measured gamma-ray properties of associated LAT sources can be used to describe the gamma-ray behavior of more-numerous source classes. Using classification techniques exploiting only these gamma-ray properties, we separate the LAT 2FGL catalog sources into pulsar and AGN candidates. 
Elizabeth C. Ferrara, Roopesh Ojha, Maria Elena Monzani, Nicola Omodei
astro-ph.HE