TY  - BOOK
AU  - Logan,John David
TI  - Invariant variational principles
SN  - 0124547508 :
U1  - 517.4 
PY  - 1977///
CY  - New York
PB  - Academic Press
KW  - Calculus of variations
KW  - Invariants
KW  - Transformations (Mathematics)
N1  - Includes index; Bibliography: p. 165-168
ER  -