A note on the Weierstrass condition in the calculus of variations
Authors:
M. R. Hestenes and W. T. Reid
Journal:
Bull. Amer. Math. Soc. 45 (1939), 471-473
DOI:
https://doi.org/10.1090/S0002-9904-1939-07015-8
MathSciNet review:
1564006
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