MathSciDoc: An Archive for Mathematician ∫

@inproceedings{l.1938necessary,
  title={Necessary conditions in the calculus of variations},
  author={L. C. Young},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203112437717592},
  booktitle={Acta Mathematica},
  volume={69},
  number={1},
  pages={229-258},
  year={1938},
}