http://science.journalfeeds.com/astronomy-astrophysics/journal-of-geophysical-research-space-physics/jplusc-gaim-on-the-impact-of-using-cosmic-and-ground-based-gps-measurements-to-estimate-ionospheric-parameters/20100209/ the knowledge syndicate Thu, 08 Sep 2011 04:02:39 +0000 hourly 1 http://wordpress.org/?v=3.0.1