ÚFAL at MRP 2020: Permutation-invariant Semantic Parsing in PERIN. In: Proceedings of the CoNLL 2020 Shared Task: Cross-Framework Meaning Representation Parsing, pp. 53-64, Association for Computational Linguistics, Stroudsburg, PA, USA, ISBN 978-1-952148-64-4 (url, local PDF, bibtex)