Gupta, G. R., Banerjee, D., Teriaca, L., Imada, S., & Solanki, S. (2010). Accelerating Waves in Polar Coronal Holes as Seen by EIS and SUMER. Astrophysical Journal, 718(1), 11-22. doi:10.1088/0004-637X/718/1/11.