PTChem congresses 1. Guidelines and recommendations for Congress organizers 2. Abstract books from PTChem Scientific Congresses September 14-18, 2026 Bydgoszcz September 22-26, 2025 Wrocław September 15-20, 2024 Poznań September 18-22, 2023 Toruń September 11-16, 2022 Lublin September 13-27, 2020/2021 Łódź