TY  - BOOK
AU  - Gerald, Williams
TI  - understanding boundary value problems, wely functions and differential operations . 
SN  - 9781639875481
AV  - QA379.U53 
PY  - 2021///
CY  - New York
PB  - Murphy & Moore publishing
KW  - Boundary value problem
KW  - Boundary value problem- Weyl theory
KW  - Differential operators
KW  - Differential questions
N1  - includes bibliographic and index
ER  -