Close Evaluation of long term solar activity effects on GPS derived TEC,
Mansoori, A. A., A. K. Parvaiz, A. Rafi, A. Roshni, A. M. Aslam, B. Shivangi, M. Bhupendra, et al. (2016),
Journal of Physics: Conference Series, 759 p. 012069,
10.1088/1742-6596/759/1/012069.