TY - JOUR TI - Introduction AU - Kowalczyk, Karol TI - Introduction AB - VL - 2017 IS - 20 (4) PY - 2017 SN - 1426-5915 C1 - 2543-859X SP - 5 EP - 6 UR - https://ejournals.eu/en/journal/pkgkptg/article/wprowadzenie-22