TY  - BOOK
AU  - Littmann Mark,1939
TI  - Planets beyond: discovering the outer solar system 
SN  - 104761128X
PY  - 1988///
CY  - New York
PB  - Wiley
KW  -  Uranus(planet)
KW  -  Neptune(planet)
KW  -  Pluto(planet)
N1  - Includes bibliographies and index
ER  -