Text ( visual ) : unmediated The American ephemeris and nautical almanac for the year 1971 / issued by the Nautical Almanac Office United States Naval Observatory, Her Majesty's Nautical Almanac Office Royal Greenwich Observatory. -- Washington : U.S. G.P.O. , 1969. -- xvii, 520 p. : ill. ; 27 cm. -- Includes index. -- (BA8391632X) ; https://ci.nii.ac.jp/ncid/BA8391632X Author Heading(s): United States Naval Observatory. Nautical Almanac Office ; Royal Greenwich Observatory ; Great Britain. Nautical Almanac Office