@preamble("
  \newcommand{\doi}[1]{%\newline
    \href{http://dx.doi.org/#1}{doi:\nolinkurl{#1}}}")

@article{N1963,
  author={Crispin St. John Alvah Nash-Williams},
  title={On Well-Quasi-Ordering Finite Trees},
  journal={Proceedings of the Cambridge Philosophical Society},
  volume=59,
  number=4,
  year=1963,
  pages={833-835},
  note={\doi{10.1017/S0305004100003844}},
}
