@misc{oberdick:mleftright,
  author = {Oberdick, Heiko},
  date = {2016-05-16},
  title = {The {\ttfamily mleftright} package},
  url = {https://ctan.org/pkg/mleftright}
}

@misc{segletes:scalerel,
  title = {{\ttfamily scalerel} -- Constrained scaling and stretching of objects},
  author = {Segletes, Steven B.},
  date = {2016-12-29},
  url = {https://ctan.org/pkg/scalerel}
}