Pejabat Almanak Nautika, Balai Cerap Tentera Laut Amerika Syarikat (1961). Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac. H.M. Stationery Office, London. m/s. 24, 26. Unknown parameter |coauthors= ignored (|author= suggested) (bantuan)
