A correlation analysis of flux ratios and the Doppler factor for EGRET   AGN sources
  We present a correlation analysis between the flux ratio of high-energy gamma-ray emission to synchrotron emission and the Doppler factor for a sample of EGRET AGNs. The results favor a model that attributes the EGRET emission of AGNs to inverse-Compton scattering on photons external to the jet. 
L.H. Huang, D.R. Jiang, Xinwu Cao (Shanghai Observatory, China)