TY  - GEN
AU  - Downs, J. W
TI  - Practical conic sections: the geometric properties of ellipses, parabolas and hyperbolas
SN  - 9780486428765
U1  - 516.15 
PY  - 1993///
CY  - New York
PB  - Dover Publication
KW  - Conic sections
ER  -