The Astronomical Almanac For the Year 1981 
U S Government Printing Office                               
 - Washington  U. S. Government Printing Office  1980 
 - [various pagings.] 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Almanacs<br/>Ephemerides<br/>NASA Thesaurus
<br/><br/><label>Universal Decimal Class. No.: </label>(059):52  / NAU-81