TY  - BOOK
AU  - Hetherington, Norriss S.
TI  - Planetary motions :  a historical perspective 
T2  - Greenwood Guides to Great Ideas in Science
SN  - 0-313-33241-X
PY  - 2006///
CY  -  Westport
PB  - Greenwood Press
KW  - AstronomyEccentricsEpicyclesEudoxusGravityIsaac NewtonMathematicsPhysics
ER  -