@inproceedings{przepiorkowski-adam:2021,
  author    = {Przepiórkowski, Adam},
  title     = {Three improvements to the HPSG model theory},
  booktitle = {{Proceedings of the 28th International Conference on Head-Driven Phrase Structure Grammar, Online (Frankfurt\slash Main)}},
  editor    = {Müller, Stefan and Melnik, Nurit},
  OPTissn   = {1535-1793},
  doi       = {10.21248/hpsg.2021.9},
  publisher = {University Library},
  address   = {Frankfurt/Main},
  pages     = {165--185},
  year      = {2021},
}

@inproceedings{przepiorkowski-adam:2021-cr,
  crossref  = {HPSG2021},
  author    = {Przepiórkowski, Adam},
  title     = {Three improvements to the HPSG model theory},
  doi       = {10.21248/hpsg.2021.9},
  pages     = {165--185},
}

@proceedings{HPSG2021,
  editor    = {Müller, Stefan and Melnik, Nurit},
  title     = {{Proceedings of the 28th International Conference on Head-Driven Phrase Structure Grammar, Online (Frankfurt\slash Main)}},
  booktitle = {{Proceedings of the 28th International Conference on Head-Driven Phrase Structure Grammar, Online (Frankfurt\slash Main)}},
  publisher = {University Library},
  address   = {Frankfurt/Main},
  OPTissn   = {1535-1793},
  year      = {2021},
}