Gokani, S 2012Maurya, AK, Veenadhari, B, Singh, R, Kumar, S, Cohen, MB, Selvakumaran, R, Gokani, S, Pant, P, Singh, AK Nighttime D region electron density measurements from ELF-VLF tweek radio atmospherics recorded at low latitudes PDF (Online Viewing) 2012-16.pdf