The astronomical almanac for the year 1991 
U.S.Government Printing Office                               
 - Washington  U. S. Government Printing Office  1990 
 - [various pagings.] 
<br/><br/><label>ISBN: </label>0-11-886938-8 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Almanacs<br/>Ephemerides<br/>NASA
<br/><br/><label>Universal Decimal Class. No.: </label>059:52  / AAL-91