TY  - BOOK
AU  - Kauffman, Robert M. and Others
AU  - Reed, Thomas T. ; jt. auth.
AU  - Zettl, Anton ; jt. auth.
TI  - Deficiency index problem for powers of ordinary differential expressions
T2  - Lecture notes in Mathematics
U1  - 515.35 
PY  - 1977///
CY  - Berlin
PB  - Springer-Verlag
ER  -