A note on the Jacobi condition for parametric problems in the calculus of variations
Author:
M. R. Hestenes
Journal:
Bull. Amer. Math. Soc. 40 (1934), 297-302
DOI:
https://doi.org/10.1090/S0002-9904-1934-05855-5
MathSciNet review:
1562840
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