Huang G, Zhang Q, FU W and Guo H. (2015) GPS/GLONASS time offset monitoring based on combined Precise Point Positioning (PPP) approach. Journal of Advances in Space Research, 55, 2950-2960.10.1016/j.asr.2015.03.003
Riley WJ. (2008) NIST special Publication 1065 Handbook of Frequency Stability Analysis, US government printing office, Washington.10.6028/NIST.SP.1065