TY  - BOOK
AU  - Yakubovich V A
AU  -  Starzhinskii V M
TI  - Linear differential equations with periodic coeffi
SN  - 0 7065 1480 7
U1  - B33,2, L5.1 
PY  - 1975///
CY  - New York
PB  - Wiley         
KW  - Equations
ER  -