TY  - DATA
AU  - Robert M. Kauffman
AU  -  Anton Zettl
AU  -  Thomas T. Read
TI  - The Deficiency Index Problem for Powers of Ordinary Differential Expressions
T2  - Lecture Notes in Mathematics
SN  - 9783540370246
PY  - 1977///
CY  - Heidelberg
PB  - Springer Berlin
KW  - Mathematics and Statistics
UR  - https://doi.org/10.1007/BFb0064277
ER  -