How to define modeling languages?

Benoît Combemale, Jeff Gray 0001, Bernhard Rumpe. How to define modeling languages?. Software and Systems Modeling, 22(2):449-451, April 2023. [doi]

@article{CombemaleGR23,
  title = {How to define modeling languages?},
  author = {Benoît Combemale and Jeff Gray 0001 and Bernhard Rumpe},
  year = {2023},
  month = {April},
  doi = {10.1007/s10270-023-01098-1},
  url = {https://doi.org/10.1007/s10270-023-01098-1},
  researchr = {https://researchr.org/publication/CombemaleGR23},
  cites = {0},
  citedby = {0},
  journal = {Software and Systems Modeling},
  volume = {22},
  number = {2},
  pages = {449-451},
}