Two-photon interference with two independent pseudo-thermal sources
  The nature of two-photon interference is a subject that has aroused renewed interest in recent years and is still under debate. In this paper we report the first observation of two-photon interference with independent pseudo-thermal sources in which sub-wavelength interference is observed. The phenomenon may be described in terms of the classical statistical distribution of the two sources and their optical transfer functions. 
Yan-Hua Zhai, Xi-Hao Chen and Ling-An Wu