C. Watson, R. B. Langley, D. R. Themens, A. W. Yau, A. D. Howarth, and P. T. Jayachandran. Enhanced Polar Outflow Probe ionospheric radio occultation measurements at high latitudes: Receiver bias estimation and comparison with ground‐based observations. Radio Science, American Geophysical Union, volume 53,  2018 .

Y. Shen, D. J. Knudsen, J. K. Burchill, A. Howarth, A. Yau, R. J. Redmon, D. M. Miles, R. H. Varney, and M. J. Nicolls. Strong ambipolar-driven ion upflow within the cleft ion fountain during low geomagnetic activity. J. Geophys. Res. Space Physics, issue 121,  2016 .