1. Carrington, R. C. 1863, Observations of Spots on the Sun (London: Williams and Norgate)
2. CCSDS 1990, Time Code Formats, Tech. Rep. CCSDS 301.0-B-2, Consultative Committee for Space Data Systems Secretariate, Communications and Data Systems Division, (Code-OS), National Aeronautics and Space Administration, Washington, DC 20546, USA
3. The SOHO mission: An overview
4. Heliospheric coordinate systems