TY  - BOOK
AU  - Downs,J.W.
TI  - Practical conic sections: The geometric properties ellipses, parabolas and hyperbolas 
SN  - 0-486-42876-1
PY  - 2003///
CY  - Mineola, N.Y.
PB  - Dover
KW  - Conic sections
ER  -