@article{Nicolls2007a,
  author = "M. J. Nicolls and C. J. Heinselman and E. A. Hope and S. Ranjan and M. C. Kelley and J. D. Kelly",
  title = "Imaging of Polar Mesosphere Summer Echoes with the 450 MHz Poker Flat Advanced Modular Incoherent Scatter Radar",
  year =  2007 ,
  journal = "Geophys. Res. Lett.",
  volume = 34,
  number = 2,
  keywords = "amisr, pfisr",
  doi = "10.1029/2007GL031476"
}