TY  - BOOK
AU  - Coddington Earl A
AU  -  Snoo H S V
TI  - Regular boundary value problems associated with pair of ordinary differential expressions
T2  - Lecture notes in mathematics; 858
U1  - B33, M12 
PY  - 1981///
CY  - Berlin
PB  - Springer-Verlag         
KW  - Differential equations
ER  -