TY  - BOOK
AU  - Etgen, Garrest J. 
TI  - A Introduction to Ordinary Differential Equations : with difference equations numerical methods and applications 
SN  - 0-06-041913-X
U1  - 515.352 
PY  - 1977///
CY  - New York 
PB  - Harper& Row, Publishers 
ER  -